management.py

# Django management-related functions, including "CREATE TABLE" generation and
# development-server initialization.

import django
from django.core.exceptions import ImproperlyConfigured
from optparse import OptionParser
from django.utils import termcolors
from django.conf import settings
import os, re, shutil, sys, textwrap

try:
    set
except NameError:
    from sets import Set as set   # Python 2.3 fallback

# For backwards compatibility: get_version() used to be in this module.
get_version = django.get_version

MODULE_TEMPLATE = '''    {%% if perms.%(app)s.%(addperm)s or perms.%(app)s.%(changeperm)s %%}
    <tr>
        <th>{%% if perms.%(app)s.%(changeperm)s %%}<a href="%(app)s/%(mod)s/">{%% endif %%}%(name)s{%% if perms.%(app)s.%(changeperm)s %%}</a>{%% endif %%}</th>
        <td class="x50">{%% if perms.%(app)s.%(addperm)s %%}<a href="%(app)s/%(mod)s/add/" class="addlink">{%% endif %%}Add{%% if perms.%(app)s.%(addperm)s %%}</a>{%% endif %%}</td>
        <td class="x75">{%% if perms.%(app)s.%(changeperm)s %%}<a href="%(app)s/%(mod)s/" class="changelink">{%% endif %%}Change{%% if perms.%(app)s.%(changeperm)s %%}</a>{%% endif %%}</td>
    </tr>
    {%% endif %%}'''

APP_ARGS = '[appname ...]'

# Use django.__path__[0] because we don't know which directory django into
# which has been installed.
PROJECT_TEMPLATE_DIR = os.path.join(django.__path__[0], 'conf', '%s_template')

INVALID_PROJECT_NAMES = ('django', 'site', 'test')

# Set up the terminal color scheme.
class dummy: pass
style = dummy()
style.ERROR = termcolors.make_style(fg='red', opts=('bold',))
style.ERROR_OUTPUT = termcolors.make_style(fg='red', opts=('bold',))
style.NOTICE = termcolors.make_style(fg='red')
style.SQL_FIELD = termcolors.make_style(fg='green', opts=('bold',))
style.SQL_COLTYPE = termcolors.make_style(fg='green')
style.SQL_KEYWORD = termcolors.make_style(fg='yellow')
style.SQL_TABLE = termcolors.make_style(opts=('bold',))
del dummy

def disable_termcolors():
    class dummy:
        def __getattr__(self, attr):
            return lambda x: x
    global style
    style = dummy()

# Disable terminal coloring on Windows, Pocket PC, or if somebody's piping the output.
if sys.platform == 'win32' or sys.platform == 'Pocket PC' or not sys.stdout.isatty():
    disable_termcolors()

def _is_valid_dir_name(s):
    return bool(re.search(r'^\w+$', s))

def _get_installed_models(table_list):
    "Gets a set of all models that are installed, given a list of existing tables"
    from django.db import backend, models
    all_models = []
    for app in models.get_apps():
        for model in models.get_models(app):
            all_models.append(model)
    if backend.uses_case_insensitive_names:
        converter = str.upper
    else:
        converter = lambda x: x
    return set([m for m in all_models if converter(m._meta.db_table) in map(converter, table_list)])

def _get_table_list():
    "Gets a list of all db tables that are physically installed."
    from django.db import connection, get_introspection_module
    cursor = connection.cursor()
    return get_introspection_module().get_table_list(cursor)

def _get_sequence_list():
    "Returns a list of information about all DB sequences for all models in all apps"
    from django.db import models

    apps = models.get_apps()
    sequence_list = []

    for app in apps:
        for model in models.get_models(app):
            for f in model._meta.fields:
                if isinstance(f, models.AutoField):
                    sequence_list.append({'table':model._meta.db_table,'column':f.column,})
                    break # Only one AutoField is allowed per model, so don't bother continuing.

            for f in model._meta.many_to_many:
                sequence_list.append({'table':f.m2m_db_table(),'column':None,})

    return sequence_list

def get_sql_create(app):
    "Returns a list of the CREATE TABLE SQL statements for the given app."
    from django.db import models
    from django.conf import settings

    if settings.DATABASE_ENGINE == 'dummy':
        # This must be the "dummy" database backend, which means the user
        # hasn't set DATABASE_ENGINE.
        sys.stderr.write(style.ERROR("Error: Django doesn't know which syntax to use for your SQL statements,\n" +
            "because you haven't specified the DATABASE_ENGINE setting.\n" +
            "Edit your settings file and change DATABASE_ENGINE to something like 'postgresql' or 'mysql'.\n"))
        sys.exit(1)

    # Get installed models, so we generate REFERENCES right.
    # We trim models from the current app so that the sqlreset command does not
    # generate invalid SQL (leaving models out of known_models is harmless, so
    # we can be conservative).
    app_models = models.get_models(app)
    final_output = []
    known_models = set([model for model in _get_installed_models(_get_table_list()) if model not in app_models])
    pending_references = {}

    for model in app_models:
        output, references = _get_sql_model_create(model, known_models)
        final_output.extend(output)
        for refto, refs in references.items():
            pending_references.setdefault(refto,[]).extend(refs)
        final_output.extend(_get_sql_for_pending_references(model, pending_references))
        # Keep track of the fact that we've created the table for this model.
        known_models.add(model)

    # Create the many-to-many join tables.
    for model in app_models:
        final_output.extend(_get_many_to_many_sql_for_model(model))

    # Handle references to tables that are from other apps
    # but don't exist physically
    not_installed_models = set(pending_references.keys())
    if not_installed_models:
        alter_sql = []
        for model in not_installed_models:
            alter_sql.extend(['-- ' + sql for sql in
                _get_sql_for_pending_references(model, pending_references)])
        if alter_sql:
            final_output.append('-- The following references should be added but depend on non-existent tables:')
            final_output.extend(alter_sql)

    return final_output
get_sql_create.help_doc = "Prints the CREATE TABLE SQL statements for the given app name(s)."
get_sql_create.args = APP_ARGS

def _get_sql_model_create(model, known_models=set()):
    """
    Get the SQL required to create a single model.

    Returns list_of_sql, pending_references_dict
    """
    from django.db import backend, models

    opts = model._meta
    final_output = []
    table_output = []
    pending_references = {}
    for f in opts.fields:
        col_type = f.db_type()
        tablespace = f.db_tablespace or opts.db_tablespace
        if col_type is None:
            # Skip ManyToManyFields, because they're not represented as
            # database columns in this table.
            continue
        # Make the definition (e.g. 'foo VARCHAR(30)') for this field.
        field_output = [style.SQL_FIELD(backend.quote_name(f.column)),
            style.SQL_COLTYPE(col_type)]
        field_output.append(style.SQL_KEYWORD('%sNULL' % (not f.null and 'NOT ' or '')))
        if (f.unique and (not f.primary_key or backend.allows_unique_and_pk)) or (f.primary_key and backend.pk_requires_unique):
            field_output.append(style.SQL_KEYWORD('UNIQUE'))
        if f.primary_key:
            field_output.append(style.SQL_KEYWORD('PRIMARY KEY'))
        if tablespace and backend.supports_tablespaces and (f.unique or f.primary_key) and backend.autoindexes_primary_keys:
            # We must specify the index tablespace inline, because we
            # won't be generating a CREATE INDEX statement for this field.
            field_output.append(backend.get_tablespace_sql(tablespace, inline=True))
        if f.rel:
            if f.rel.to in known_models:
                field_output.append(style.SQL_KEYWORD('REFERENCES') + ' ' + \
                    style.SQL_TABLE(backend.quote_name(f.rel.to._meta.db_table)) + ' (' + \
                    style.SQL_FIELD(backend.quote_name(f.rel.to._meta.get_field(f.rel.field_name).column)) + ')' +
                    backend.get_deferrable_sql()
                )
            else:
                # We haven't yet created the table to which this field
                # is related, so save it for later.
                pr = pending_references.setdefault(f.rel.to, []).append((model, f))
        table_output.append(' '.join(field_output))
    if opts.order_with_respect_to:
        table_output.append(style.SQL_FIELD(backend.quote_name('_order')) + ' ' + \
            style.SQL_COLTYPE(models.IntegerField().db_type()) + ' ' + \
            style.SQL_KEYWORD('NULL'))
    for field_constraints in opts.unique_together:
        table_output.append(style.SQL_KEYWORD('UNIQUE') + ' (%s)' % \
            ", ".join([backend.quote_name(style.SQL_FIELD(opts.get_field(f).column)) for f in field_constraints]))

    full_statement = [style.SQL_KEYWORD('CREATE TABLE') + ' ' + style.SQL_TABLE(backend.quote_name(opts.db_table)) + ' (']
    for i, line in enumerate(table_output): # Combine and add commas.
        full_statement.append('    %s%s' % (line, i < len(table_output)-1 and ',' or ''))
    full_statement.append(')')
    if opts.db_tablespace and backend.supports_tablespaces:
        full_statement.append(backend.get_tablespace_sql(opts.db_tablespace))
    full_statement.append(';')
    final_output.append('\n'.join(full_statement))

    if opts.has_auto_field and hasattr(backend, 'get_autoinc_sql'):
        # Add any extra SQL needed to support auto-incrementing primary keys
        autoinc_sql = backend.get_autoinc_sql(opts.db_table)
        if autoinc_sql:
            for stmt in autoinc_sql:
                final_output.append(stmt)

    return final_output, pending_references

def _get_sql_for_pending_references(model, pending_references):
    """
    Get any ALTER TABLE statements to add constraints after the fact.
    """
    from django.db import backend
    from django.db.backends.util import truncate_name

    final_output = []
    if backend.supports_constraints:
        opts = model._meta
        if model in pending_references:
            for rel_class, f in pending_references[model]:
                rel_opts = rel_class._meta
                r_table = rel_opts.db_table
                r_col = f.column
                table = opts.db_table
                col = opts.get_field(f.rel.field_name).column
                # For MySQL, r_name must be unique in the first 64 characters.
                # So we are careful with character usage here.
                r_name = '%s_refs_%s_%x' % (r_col, col, abs(hash((r_table, table))))
                final_output.append(style.SQL_KEYWORD('ALTER TABLE') + ' %s ADD CONSTRAINT %s FOREIGN KEY (%s) REFERENCES %s (%s)%s;' % \
                    (backend.quote_name(r_table), truncate_name(r_name, backend.get_max_name_length()),
                    backend.quote_name(r_col), backend.quote_name(table), backend.quote_name(col),
                    backend.get_deferrable_sql()))
            del pending_references[model]
    return final_output

def _get_many_to_many_sql_for_model(model):
    from django.db import backend, models
    from django.contrib.contenttypes import generic

    opts = model._meta
    final_output = []
    for f in opts.many_to_many:
        if not isinstance(f.rel, generic.GenericRel):
            tablespace = f.db_tablespace or opts.db_tablespace
            if tablespace and backend.supports_tablespaces and backend.autoindexes_primary_keys:
                tablespace_sql = ' ' + backend.get_tablespace_sql(tablespace, inline=True)
            else:
                tablespace_sql = ''
            table_output = [style.SQL_KEYWORD('CREATE TABLE') + ' ' + \
                style.SQL_TABLE(backend.quote_name(f.m2m_db_table())) + ' (']
            table_output.append('    %s %s %s%s,' % \
                (style.SQL_FIELD(backend.quote_name('id')),
                style.SQL_COLTYPE(models.AutoField(primary_key=True).db_type()),
                style.SQL_KEYWORD('NOT NULL PRIMARY KEY'),
                tablespace_sql))
            table_output.append('    %s %s %s %s (%s)%s,' % \
                (style.SQL_FIELD(backend.quote_name(f.m2m_column_name())),
                style.SQL_COLTYPE(models.ForeignKey(model).db_type()),
                style.SQL_KEYWORD('NOT NULL REFERENCES'),
                style.SQL_TABLE(backend.quote_name(opts.db_table)),
                style.SQL_FIELD(backend.quote_name(opts.pk.column)),
                backend.get_deferrable_sql()))
            table_output.append('    %s %s %s %s (%s)%s,' % \
                (style.SQL_FIELD(backend.quote_name(f.m2m_reverse_name())),
                style.SQL_COLTYPE(models.ForeignKey(f.rel.to).db_type()),
                style.SQL_KEYWORD('NOT NULL REFERENCES'),
                style.SQL_TABLE(backend.quote_name(f.rel.to._meta.db_table)),
                style.SQL_FIELD(backend.quote_name(f.rel.to._meta.pk.column)),
                backend.get_deferrable_sql()))
            table_output.append('    %s (%s, %s)%s' % \
                (style.SQL_KEYWORD('UNIQUE'),
                style.SQL_FIELD(backend.quote_name(f.m2m_column_name())),
                style.SQL_FIELD(backend.quote_name(f.m2m_reverse_name())),
                tablespace_sql))
            table_output.append(')')
            if opts.db_tablespace and backend.supports_tablespaces:
                # f.db_tablespace is only for indices, so ignore its value here.
                table_output.append(backend.get_tablespace_sql(opts.db_tablespace))
            table_output.append(';')
            final_output.append('\n'.join(table_output))

            # Add any extra SQL needed to support auto-incrementing PKs
            autoinc_sql = backend.get_autoinc_sql(f.m2m_db_table())
            if autoinc_sql:
                for stmt in autoinc_sql:
                    final_output.append(stmt)

    return final_output

def get_sql_delete(app):
    "Returns a list of the DROP TABLE SQL statements for the given app."
    from django.db import backend, connection, models, get_introspection_module
    from django.db.backends.util import truncate_name
    introspection = get_introspection_module()

    # This should work even if a connection isn't available
    try:
        cursor = connection.cursor()
    except:
        cursor = None

    # Figure out which tables already exist
    if cursor:
        table_names = introspection.get_table_list(cursor)
    else:
        table_names = []
    if backend.uses_case_insensitive_names:
        table_name_converter = str.upper
    else:
        table_name_converter = lambda x: x

    output = []

    # Output DROP TABLE statements for standard application tables.
    to_delete = set()

    references_to_delete = {}
    app_models = models.get_models(app)
    for model in app_models:
        if cursor and table_name_converter(model._meta.db_table) in table_names:
            # The table exists, so it needs to be dropped
            opts = model._meta
            for f in opts.fields:
                if f.rel and f.rel.to not in to_delete:
                    references_to_delete.setdefault(f.rel.to, []).append( (model, f) )

            to_delete.add(model)

    for model in app_models:
        if cursor and table_name_converter(model._meta.db_table) in table_names:
            # Drop the table now
            output.append('%s %s;' % (style.SQL_KEYWORD('DROP TABLE'),
                style.SQL_TABLE(backend.quote_name(model._meta.db_table))))
            if backend.supports_constraints and model in references_to_delete:
                for rel_class, f in references_to_delete[model]:
                    table = rel_class._meta.db_table
                    col = f.column
                    r_table = model._meta.db_table
                    r_col = model._meta.get_field(f.rel.field_name).column
                    r_name = '%s_refs_%s_%x' % (col, r_col, abs(hash((table, r_table))))
                    output.append('%s %s %s %s;' % \
                        (style.SQL_KEYWORD('ALTER TABLE'),
                        style.SQL_TABLE(backend.quote_name(table)),
                        style.SQL_KEYWORD(backend.get_drop_foreignkey_sql()),
                        style.SQL_FIELD(truncate_name(r_name, backend.get_max_name_length()))))
                del references_to_delete[model]
            if model._meta.has_auto_field and hasattr(backend, 'get_drop_sequence'):
                output.append(backend.get_drop_sequence(model._meta.db_table))

    # Output DROP TABLE statements for many-to-many tables.
    for model in app_models:
        opts = model._meta
        for f in opts.many_to_many:
            if cursor and table_name_converter(f.m2m_db_table()) in table_names:
                output.append("%s %s;" % (style.SQL_KEYWORD('DROP TABLE'),
                    style.SQL_TABLE(backend.quote_name(f.m2m_db_table()))))
                if hasattr(backend, 'get_drop_sequence'):
                    output.append(backend.get_drop_sequence("%s_%s" % (model._meta.db_table, f.column)))


    app_label = app_models[0]._meta.app_label

    # Close database connection explicitly, in case this output is being piped
    # directly into a database client, to avoid locking issues.
    if cursor:
        cursor.close()
        connection.close()

    return output[::-1] # Reverse it, to deal with table dependencies.
get_sql_delete.help_doc = "Prints the DROP TABLE SQL statements for the given app name(s)."
get_sql_delete.args = APP_ARGS

def get_sql_reset(app):
    "Returns a list of the DROP TABLE SQL, then the CREATE TABLE SQL, for the given module."
    return get_sql_delete(app) + get_sql_all(app)
get_sql_reset.help_doc = "Prints the DROP TABLE SQL, then the CREATE TABLE SQL, for the given app name(s)."
get_sql_reset.args = APP_ARGS

def get_sql_flush():
    "Returns a list of the SQL statements used to flush the database"
    from django.db import backend
    statements = backend.get_sql_flush(style, _get_table_list(), _get_sequence_list())
    return statements
get_sql_flush.help_doc = "Returns a list of the SQL statements required to return all tables in the database to the state they were in just after they were installed."
get_sql_flush.args = ''

def get_custom_sql_for_model(model):
    from django.db import models
    from django.conf import settings

    opts = model._meta
    app_dir = os.path.normpath(os.path.join(os.path.dirname(models.get_app(model._meta.app_label).__file__), 'sql'))
    output = []

    # Some backends can't execute more than one SQL statement at a time,
    # so split into separate statements.
    statements = re.compile(r";[ \t]*$", re.M)

    # Find custom SQL, if it's available.
    sql_files = [os.path.join(app_dir, "%s.%s.sql" % (opts.object_name.lower(), settings.DATABASE_ENGINE)),
                 os.path.join(app_dir, "%s.sql" % opts.object_name.lower())]
    for sql_file in sql_files:
        if os.path.exists(sql_file):
            fp = open(sql_file, 'U')
            for statement in statements.split(fp.read().decode(settings.FILE_CHARSET)):
                # Remove any comments from the file
                statement = re.sub(ur"--.*[\n\Z]", "", statement)
                if statement.strip():
                    output.append(statement + u";")
            fp.close()

    return output

def get_custom_sql(app):
    "Returns a list of the custom table modifying SQL statements for the given app."
    from django.db.models import get_models
    output = []

    app_models = get_models(app)
    app_dir = os.path.normpath(os.path.join(os.path.dirname(app.__file__), 'sql'))

    for model in app_models:
        output.extend(get_custom_sql_for_model(model))

    return output
get_custom_sql.help_doc = "Prints the custom table modifying SQL statements for the given app name(s)."
get_custom_sql.args = APP_ARGS

def get_sql_initial_data(apps):
    "Returns a list of the initial INSERT SQL statements for the given app."
    return style.ERROR("This action has been renamed. Try './manage.py sqlcustom %s'." % ' '.join(apps and apps or ['app1', 'app2']))
get_sql_initial_data.help_doc = "RENAMED: see 'sqlcustom'"
get_sql_initial_data.args = ''

def get_sql_sequence_reset(app):
    "Returns a list of the SQL statements to reset sequences for the given app."
    from django.db import backend, models
    return backend.get_sql_sequence_reset(style, models.get_models(app))
get_sql_sequence_reset.help_doc = "Prints the SQL statements for resetting sequences for the given app name(s)."
get_sql_sequence_reset.args = APP_ARGS

def get_sql_indexes(app):
    "Returns a list of the CREATE INDEX SQL statements for all models in the given app."
    from django.db import models
    output = []
    for model in models.get_models(app):
        output.extend(get_sql_indexes_for_model(model))
    return output
get_sql_indexes.help_doc = "Prints the CREATE INDEX SQL statements for the given model module name(s)."
get_sql_indexes.args = APP_ARGS

def get_sql_indexes_for_model(model):
    "Returns the CREATE INDEX SQL statements for a single model"
    from django.db import backend
    output = []

    for f in model._meta.fields:
        if f.db_index and not ((f.primary_key or f.unique) and backend.autoindexes_primary_keys):
            unique = f.unique and 'UNIQUE ' or ''
            tablespace = f.db_tablespace or model._meta.db_tablespace
            if tablespace and backend.supports_tablespaces:
                tablespace_sql = ' ' + backend.get_tablespace_sql(tablespace)
            else:
                tablespace_sql = ''
            output.append(
                style.SQL_KEYWORD('CREATE %sINDEX' % unique) + ' ' + \
                style.SQL_TABLE(backend.quote_name('%s_%s' % (model._meta.db_table, f.column))) + ' ' + \
                style.SQL_KEYWORD('ON') + ' ' + \
                style.SQL_TABLE(backend.quote_name(model._meta.db_table)) + ' ' + \
                "(%s)" % style.SQL_FIELD(backend.quote_name(f.column)) + \
                "%s;" % tablespace_sql
            )
    return output

def get_sql_evolution(app):
    "Returns SQL to update an existing schema to match the existing models."
    from django.db import get_creation_module, models, backend, get_introspection_module, connection
    data_types = get_creation_module().DATA_TYPES

    if not data_types:
        # This must be the "dummy" database backend, which means the user
        # hasn't set DATABASE_ENGINE.
        sys.stderr.write(style.ERROR("Error: Django doesn't know which syntax to use for your SQL statements,\n" +
            "because you haven't specified the DATABASE_ENGINE setting.\n" +
            "Edit your settings file and change DATABASE_ENGINE to something like 'postgresql' or 'mysql'.\n"))
        sys.exit(1)

    # First, try validating the models.
    _check_for_validation_errors()

    final_output = []

    # stolen and trimmed from syncdb so that we know which models are about 
    # to be created (so we don't check them for updates)
    table_list = _get_table_list()
    seen_models = _get_installed_models(table_list)
    created_models = set()
    pending_references = {}

    model_list = models.get_models(app)
    for model in model_list:
        # Create the model's database table, if it doesn't already exist.
        if model._meta.db_table in table_list or model._meta.aka in table_list or len(set(model._meta.aka) & set(table_list))>0:
            continue
        sql, references = _get_sql_model_create(model, seen_models)
        seen_models.add(model)
        created_models.add(model)
        table_list.append(model._meta.db_table)

    introspection = get_introspection_module()
    # This should work even if a connecton isn't available
    try:
        cursor = connection.cursor()
    except:
        cursor = None

    # get the existing models, minus the models we've just created
    app_models = models.get_models(app)
    for model in created_models:
        if model in app_models:
            app_models.remove(model)

    for klass in app_models:
        
        output, new_table_name = get_sql_evolution_check_for_changed_model_name(klass)
        final_output.extend(output)
        
        output = get_sql_evolution_check_for_changed_field_flags(klass, new_table_name)
        final_output.extend(output)
    
        output = get_sql_evolution_check_for_changed_field_name(klass, new_table_name)
        final_output.extend(output)
        
        output = get_sql_evolution_check_for_new_fields(klass, new_table_name)
        final_output.extend(output)
        
        output = get_sql_evolution_check_for_dead_fields(klass, new_table_name)
        final_output.extend(output)
        
    return final_output
get_sql_evolution.help_doc = "Returns SQL to update an existing schema to match the existing models."
get_sql_evolution.args = APP_ARGS

def get_sql_evolution_check_for_new_fields(klass, new_table_name):
    "checks for model fields that are not in the existing data structure"
    from django.db import backend, get_creation_module, models, get_introspection_module, connection
    data_types = get_creation_module().DATA_TYPES
    cursor = connection.cursor()
    introspection = get_introspection_module()
    opts = klass._meta
    output = []
    db_table = klass._meta.db_table
    if new_table_name: 
        db_table = new_table_name
    for f in opts.fields:
        existing_fields = introspection.get_columns(cursor,db_table)
        if f.column not in existing_fields and (not f.aka or f.aka not in existing_fields and len(set(f.aka) & set(existing_fields))==0):
            rel_field = f
            data_type = f.get_internal_type()
            col_type = data_types[data_type]
            if col_type is not None:
                output.append( backend.get_add_column_sql( db_table, f.column, style.SQL_COLTYPE(col_type % rel_field.__dict__), f.null, f.unique, f.primary_key ) )
    return output

def get_sql_evolution_check_for_changed_model_name(klass):
    from django.db import backend, get_creation_module, models, get_introspection_module, connection
    cursor = connection.cursor()
    introspection = get_introspection_module()
    table_list = introspection.get_table_list(cursor)
    if klass._meta.db_table in table_list:
        return [], None
    if klass._meta.aka in table_list:
        return [ backend.get_change_table_name_sql( klass._meta.db_table, klass._meta.aka) ], klass._meta.aka
    elif len(set(klass._meta.aka) & set(table_list))==1:
        return [ backend.get_change_table_name_sql( klass._meta.db_table, klass._meta.aka[0]) ], klass._meta.aka[0]
    else:
        return [], None
    
def get_sql_evolution_check_for_changed_field_name(klass, new_table_name):
    from django.db import backend, get_creation_module, models, get_introspection_module, connection
    data_types = get_creation_module().DATA_TYPES
    cursor = connection.cursor()
    introspection = get_introspection_module()
    opts = klass._meta
    output = []
    db_table = klass._meta.db_table
    if new_table_name: 
        db_table = new_table_name
    for f in opts.fields:
        existing_fields = introspection.get_columns(cursor,db_table)
        if f.column not in existing_fields and f.aka and (f.aka in existing_fields or len(set(f.aka) & set(existing_fields)))==1:
            old_col = None
            if isinstance( f.aka, str ):
                old_col = f.aka
            else:
                old_col = f.aka[0]
            rel_field = f
            data_type = f.get_internal_type()
            col_type = data_types[data_type]
            if col_type is not None:
                field_output = []
                col_def = style.SQL_COLTYPE(col_type % rel_field.__dict__) +' '+ style.SQL_KEYWORD('%sNULL' % (not f.null and 'NOT ' or ''))
                if f.unique:
                    col_def += style.SQL_KEYWORD(' UNIQUE')
                if f.primary_key:
                    col_def += style.SQL_KEYWORD(' PRIMARY KEY')
                field_output.append( backend.get_change_column_name_sql( klass._meta.db_table, introspection.get_indexes(cursor,db_table), backend.quote_name(old_col), backend.quote_name(f.column), col_def ) )
                output.append(' '.join(field_output))
    return output
    
def get_sql_evolution_check_for_changed_field_flags(klass, new_table_name):
    from django.db import backend, get_creation_module, models, get_introspection_module, connection
    from django.db.models.fields import CharField, SlugField
    from django.db.models.fields.related import RelatedField, ForeignKey
    data_types = get_creation_module().DATA_TYPES
    cursor = connection.cursor()
    introspection = get_introspection_module()
    opts = klass._meta
    output = []
    db_table = klass._meta.db_table
    if new_table_name: 
        db_table = new_table_name
    for f in opts.fields:
        existing_fields = introspection.get_columns(cursor,db_table)
#        print existing_fields
        cf = None # current field, ie what it is before any renames
        if f.column in existing_fields:
            cf = f.column
        elif f.aka in existing_fields:
            cf = f.aka
        elif f.aka and len(set(f.aka) & set(existing_fields))==1:
            cf = f.aka[0]
        else:
            continue # no idea what column you're talking about - should be handled by get_sql_evolution_check_for_new_fields())
        data_type = f.get_internal_type()
        if data_types.has_key(data_type):
            column_flags = introspection.get_known_column_flags(cursor, db_table, cf)
#            print db_table, cf, column_flags
            if column_flags['allow_null']!=f.null or \
                    ( not f.primary_key and isinstance(f, CharField) and column_flags['maxlength']!=str(f.maxlength) ) or \
                    ( not f.primary_key and isinstance(f, SlugField) and column_flags['maxlength']!=str(f.maxlength) ) or \
                    ( column_flags['unique']!=f.unique and ( settings.DATABASE_ENGINE!='postgresql' or not f.primary_key ) ) or \
                    column_flags['primary_key']!=f.primary_key:
                    #column_flags['foreign_key']!=f.foreign_key:
#                print 'need to change'
#                print db_table, f.column, column_flags
#                print "column_flags['allow_null']!=f.null", column_flags['allow_null']!=f.null
#                print "not f.primary_key and isinstance(f, CharField) and column_flags['maxlength']!=str(f.maxlength)", not f.primary_key and isinstance(f, CharField) and column_flags['maxlength']!=str(f.maxlength)
#                print "not f.primary_key and isinstance(f, SlugField) and column_flags['maxlength']!=str(f.maxlength)", not f.primary_key and isinstance(f, SlugField) and column_flags['maxlength']!=str(f.maxlength)
#                print "column_flags['unique']!=f.unique", column_flags['unique']!=f.unique
#                print "column_flags['primary_key']!=f.primary_key", column_flags['primary_key']!=f.primary_key
                col_type = data_types[data_type]
                col_type_def = style.SQL_COLTYPE(col_type % f.__dict__)
#                col_def = style.SQL_COLTYPE(col_type % f.__dict__) +' '+ style.SQL_KEYWORD('%sNULL' % (not f.null and 'NOT ' or ''))
#                if f.unique:
#                    col_def += ' '+ style.SQL_KEYWORD('UNIQUE')
#                if f.primary_key:
#                    col_def += ' '+ style.SQL_KEYWORD('PRIMARY KEY')
                output.append( backend.get_change_column_def_sql( db_table, cf, col_type_def, f.null, f.unique, f.primary_key ) )
                    #print db_table, cf, f.maxlength, introspection.get_known_column_flags(cursor, db_table, cf)
    return output

def get_sql_evolution_check_for_dead_fields(klass, new_table_name):
    from django.db import backend, get_creation_module, models, get_introspection_module, connection
    from django.db.models.fields import CharField, SlugField
    from django.db.models.fields.related import RelatedField, ForeignKey
    data_types = get_creation_module().DATA_TYPES
    cursor = connection.cursor()
    introspection = get_introspection_module()
    opts = klass._meta
    output = []
    db_table = klass._meta.db_table
    if new_table_name: 
        db_table = new_table_name
    suspect_fields = set(introspection.get_columns(cursor,db_table))
#    print 'suspect_fields = ', suspect_fields
    for f in opts.fields:
#        print 'f = ', f
#        print 'f.aka = ', f.aka
        suspect_fields.discard(f.column)
        suspect_fields.discard(f.aka)
        if f.aka: suspect_fields.difference_update(f.aka)
    if len(suspect_fields)>0:
        output.append( '-- warning: the following may cause data loss' )
        for suspect_field in suspect_fields:
            output.extend( backend.get_drop_column_sql( db_table, suspect_field ) )
        output.append( '-- end warning' )
    return output

def get_sql_all(app):
    "Returns a list of CREATE TABLE SQL, initial-data inserts, and CREATE INDEX SQL for the given module."
    return get_sql_create(app) + get_custom_sql(app) + get_sql_indexes(app)
get_sql_all.help_doc = "Prints the CREATE TABLE, initial-data and CREATE INDEX SQL statements for the given model module name(s)."
get_sql_all.args = APP_ARGS

def _emit_post_sync_signal(created_models, verbosity, interactive):
    from django.db import models
    from django.dispatch import dispatcher
    # Emit the post_sync signal for every application.
    for app in models.get_apps():
        app_name = app.__name__.split('.')[-2]
        if verbosity >= 2:
            print "Running post-sync handlers for application", app_name
        dispatcher.send(signal=models.signals.post_syncdb, sender=app,
            app=app, created_models=created_models,
            verbosity=verbosity, interactive=interactive)

def syncdb(verbosity=1, interactive=True):
    "Creates the database tables for all apps in INSTALLED_APPS whose tables haven't already been created."
    from django.db import backend, connection, transaction, models
    from django.conf import settings

    disable_termcolors()

    # First, try validating the models.
    _check_for_validation_errors()

    # Import the 'management' module within each installed app, to register
    # dispatcher events.
    for app_name in settings.INSTALLED_APPS:
        try:
            __import__(app_name + '.management', {}, {}, [''])
        except ImportError:
            pass

    cursor = connection.cursor()

    # Get a list of all existing database tables,
    # so we know what needs to be added.
    table_list = _get_table_list()
    if backend.uses_case_insensitive_names:
        table_name_converter = str.upper
    else:
        table_name_converter = lambda x: x

    # Get a list of already installed *models* so that references work right.
    seen_models = _get_installed_models(table_list)
    created_models = set()
    pending_references = {}

    # Create the tables for each model
    for app in models.get_apps():
        app_name = app.__name__.split('.')[-2]
        model_list = models.get_models(app)
        for model in model_list:
            # Create the model's database table, if it doesn't already exist.
            if verbosity >= 2:
                print "Processing %s.%s model" % (app_name, model._meta.object_name)
            if table_name_converter(model._meta.db_table) in table_list or table_name_converter(model._meta.aka) in table_list or len(set(model._meta.aka) & set(table_list))>0:
                continue
            sql, references = _get_sql_model_create(model, seen_models)
            seen_models.add(model)
            created_models.add(model)
            for refto, refs in references.items():
                pending_references.setdefault(refto, []).extend(refs)
            sql.extend(_get_sql_for_pending_references(model, pending_references))
            if verbosity >= 1:
                print "Creating table %s" % model._meta.db_table
            for statement in sql:
                cursor.execute(statement)
            table_list.append(table_name_converter(model._meta.db_table))

    # Create the m2m tables. This must be done after all tables have been created
    # to ensure that all referred tables will exist.
    for app in models.get_apps():
        app_name = app.__name__.split('.')[-2]
        model_list = models.get_models(app)
        for model in model_list:
            if model in created_models:
                sql = _get_many_to_many_sql_for_model(model)
                if sql:
                    if verbosity >= 2:
                        print "Creating many-to-many tables for %s.%s model" % (app_name, model._meta.object_name)
                    for statement in sql:
                        cursor.execute(statement)

        for sql in get_sql_evolution(app):
            print sql
#            cursor.execute(sql)

    transaction.commit_unless_managed()

    # Send the post_syncdb signal, so individual apps can do whatever they need
    # to do at this point.
    _emit_post_sync_signal(created_models, verbosity, interactive)

    # Install custom SQL for the app (but only if this
    # is a model we've just created)
    for app in models.get_apps():
        app_name = app.__name__.split('.')[-2]
        for model in models.get_models(app):
            if model in created_models:
                custom_sql = get_custom_sql_for_model(model)
                if custom_sql:
                    if verbosity >= 1:
                        print "Installing custom SQL for %s.%s model" % (app_name, model._meta.object_name)
                    try:
                        for sql in custom_sql:
                            cursor.execute(sql)
                    except Exception, e:
                        sys.stderr.write("Failed to install custom SQL for %s.%s model: %s" % \
                                            (app_name, model._meta.object_name, e))
                        transaction.rollback_unless_managed()
                    else:
                        transaction.commit_unless_managed()

    # Install SQL indicies for all newly created models
    for app in models.get_apps():
        app_name = app.__name__.split('.')[-2]
        for model in models.get_models(app):
            if model in created_models:
                index_sql = get_sql_indexes_for_model(model)
                if index_sql:
                    if verbosity >= 1:
                        print "Installing index for %s.%s model" % (app_name, model._meta.object_name)
                    try:
                        for sql in index_sql:
                            cursor.execute(sql)
                    except Exception, e:
                        sys.stderr.write("Failed to install index for %s.%s model: %s" % \
                                            (app_name, model._meta.object_name, e))
                        transaction.rollback_unless_managed()
                    else:
                        transaction.commit_unless_managed()

    # Install the 'initialdata' fixture, using format discovery
    load_data(['initial_data'], verbosity=verbosity)
syncdb.help_doc = "Create the database tables for all apps in INSTALLED_APPS whose tables haven't already been created."
syncdb.args = '[--verbosity] [--noinput]'

def get_admin_index(app):
    "Returns admin-index template snippet (in list form) for the given app."
    from django.utils.text import capfirst
    from django.db.models import get_models
    output = []
    app_models = get_models(app)
    app_label = app_models[0]._meta.app_label
    output.append('{%% if perms.%s %%}' % app_label)
    output.append('<div class="module"><h2>%s</h2><table>' % app_label.title())
    for model in app_models:
        if model._meta.admin:
            output.append(MODULE_TEMPLATE % {
                'app': app_label,
                'mod': model._meta.module_name,
                'name': capfirst(model._meta.verbose_name_plural),
                'addperm': model._meta.get_add_permission(),
                'changeperm': model._meta.get_change_permission(),
            })
    output.append('</table></div>')
    output.append('{% endif %}')
    return output
get_admin_index.help_doc = "Prints the admin-index template snippet for the given app name(s)."
get_admin_index.args = APP_ARGS

def _module_to_dict(module, omittable=lambda k: k.startswith('_')):
    "Converts a module namespace to a Python dictionary. Used by get_settings_diff."
    return dict([(k, repr(v)) for k, v in module.__dict__.items() if not omittable(k)])

def diffsettings():
    """
    Displays differences between the current settings.py and Django's
    default settings. Settings that don't appear in the defaults are
    followed by "###".
    """
    # Inspired by Postfix's "postconf -n".
    from django.conf import settings, global_settings

    user_settings = _module_to_dict(settings._target)
    default_settings = _module_to_dict(global_settings)

    output = []
    keys = user_settings.keys()
    keys.sort()
    for key in keys:
        if key not in default_settings:
            output.append("%s = %s  ###" % (key, user_settings[key]))
        elif user_settings[key] != default_settings[key]:
            output.append("%s = %s" % (key, user_settings[key]))
    print '\n'.join(output)
diffsettings.args = ""

def reset(app, interactive=True):
    "Executes the equivalent of 'get_sql_reset' in the current database."
    from django.db import connection, transaction
    from django.conf import settings
    app_name = app.__name__.split('.')[-2]

    disable_termcolors()

    # First, try validating the models.
    _check_for_validation_errors(app)
    sql_list = get_sql_reset(app)

    if interactive:
        confirm = raw_input("""
You have requested a database reset.
This will IRREVERSIBLY DESTROY any data for
the "%s" application in the database "%s".
Are you sure you want to do this?

Type 'yes' to continue, or 'no' to cancel: """ % (app_name, settings.DATABASE_NAME))
    else:
        confirm = 'yes'

    if confirm == 'yes':
        try:
            cursor = connection.cursor()
            for sql in sql_list:
                cursor.execute(sql)
        except Exception, e:
            sys.stderr.write(style.ERROR("""Error: %s couldn't be reset. Possible reasons:
  * The database isn't running or isn't configured correctly.
  * At least one of the database tables doesn't exist.
  * The SQL was invalid.
Hint: Look at the output of 'django-admin.py sqlreset %s'. That's the SQL this command wasn't able to run.
The full error: """ % (app_name, app_name)) + style.ERROR_OUTPUT(str(e)) + '\n')
            transaction.rollback_unless_managed()
            sys.exit(1)
        transaction.commit_unless_managed()
    else:
        print "Reset cancelled."
reset.help_doc = "Executes ``sqlreset`` for the given app(s) in the current database."
reset.args = '[--noinput]' + APP_ARGS

def flush(verbosity=1, interactive=True):
    "Returns all tables in the database to the same state they were in immediately after syncdb."
    from django.conf import settings
    from django.db import connection, transaction, models
    from django.dispatch import dispatcher

    disable_termcolors()

    # First, try validating the models.
    _check_for_validation_errors()

    # Import the 'management' module within each installed app, to register
    # dispatcher events.
    for app_name in settings.INSTALLED_APPS:
        try:
            __import__(app_name + '.management', {}, {}, [''])
        except ImportError:
            pass

    sql_list = get_sql_flush()

    if interactive:
        confirm = raw_input("""
You have requested a flush of the database.
This will IRREVERSIBLY DESTROY all data currently in the database,
and return each table to the state it was in after syncdb.
Are you sure you want to do this?

Type 'yes' to continue, or 'no' to cancel: """)
    else:
        confirm = 'yes'

    if confirm == 'yes':
        try:
            cursor = connection.cursor()
            for sql in sql_list:
                cursor.execute(sql)
        except Exception, e:
            sys.stderr.write(style.ERROR("""Error: Database %s couldn't be flushed. Possible reasons:
  * The database isn't running or isn't configured correctly.
  * At least one of the expected database tables doesn't exist.
  * The SQL was invalid.
Hint: Look at the output of 'django-admin.py sqlflush'. That's the SQL this command wasn't able to run.
The full error: """ % settings.DATABASE_NAME + style.ERROR_OUTPUT(str(e)) + '\n'))
            transaction.rollback_unless_managed()
            sys.exit(1)
        transaction.commit_unless_managed()

        # Emit the post sync signal. This allows individual
        # applications to respond as if the database had been
        # sync'd from scratch.
        _emit_post_sync_signal(models.get_models(), verbosity, interactive)

        # Reinstall the initial_data fixture
        load_data(['initial_data'], verbosity=verbosity)

    else:
        print "Flush cancelled."
flush.help_doc = "Executes ``sqlflush`` on the current database."
flush.args = '[--verbosity] [--noinput]'

def _start_helper(app_or_project, name, directory, other_name=''):
    other = {'project': 'app', 'app': 'project'}[app_or_project]
    if not _is_valid_dir_name(name):
        sys.stderr.write(style.ERROR("Error: %r is not a valid %s name. Please use only numbers, letters and underscores.\n" % (name, app_or_project)))
        sys.exit(1)
    top_dir = os.path.join(directory, name)
    try:
        os.mkdir(top_dir)
    except OSError, e:
        sys.stderr.write(style.ERROR("Error: %s\n" % e))
        sys.exit(1)
    template_dir = PROJECT_TEMPLATE_DIR % app_or_project
    for d, subdirs, files in os.walk(template_dir):
        relative_dir = d[len(template_dir)+1:].replace('%s_name' % app_or_project, name)
        if relative_dir:
            os.mkdir(os.path.join(top_dir, relative_dir))
        for i, subdir in enumerate(subdirs):
            if subdir.startswith('.'):
                del subdirs[i]
        for f in files:
            if f.endswith('.pyc'):
                continue
            path_old = os.path.join(d, f)
            path_new = os.path.join(top_dir, relative_dir, f.replace('%s_name' % app_or_project, name))
            fp_old = open(path_old, 'r')
            fp_new = open(path_new, 'w')
            fp_new.write(fp_old.read().replace('{{ %s_name }}' % app_or_project, name).replace('{{ %s_name }}' % other, other_name))
            fp_old.close()
            fp_new.close()
            try:
                shutil.copymode(path_old, path_new)
            except OSError:
                sys.stderr.write(style.NOTICE("Notice: Couldn't set permission bits on %s. You're probably using an uncommon filesystem setup. No problem.\n" % path_new))

def startproject(project_name, directory):
    "Creates a Django project for the given project_name in the given directory."
    from random import choice
    if project_name in INVALID_PROJECT_NAMES:
        sys.stderr.write(style.ERROR("Error: '%r' conflicts with the name of an existing Python module and cannot be used as a project name. Please try another name.\n" % project_name))
        sys.exit(1)
    _start_helper('project', project_name, directory)

    # Create a random SECRET_KEY hash, and put it in the main settings.
    main_settings_file = os.path.join(directory, project_name, 'settings.py')
    settings_contents = open(main_settings_file, 'r').read()

    # If settings.py was copied from a read-only source, make it writeable.
    if not os.access(main_settings_file, os.W_OK):
        os.chmod(main_settings_file, 0600)

    fp = open(main_settings_file, 'w')
    secret_key = ''.join([choice('abcdefghijklmnopqrstuvwxyz0123456789!@#$%^&*(-_=+)') for i in range(50)])
    settings_contents = re.sub(r"(?<=SECRET_KEY = ')'", secret_key + "'", settings_contents)
    fp.write(settings_contents)
    fp.close()
startproject.help_doc = "Creates a Django project directory structure for the given project name in the current directory."
startproject.args = "[projectname]"

def startapp(app_name, directory):
    "Creates a Django app for the given app_name in the given directory."
    # Determine the project_name a bit naively -- by looking at the name of
    # the parent directory.
    project_dir = os.path.normpath(os.path.join(directory, '..'))
    parent_dir = os.path.basename(project_dir)
    project_name = os.path.basename(directory)
    if app_name == project_name:
        sys.stderr.write(style.ERROR("Error: You cannot create an app with the same name (%r) as your project.\n" % app_name))
        sys.exit(1)
    _start_helper('app', app_name, directory, parent_dir)
startapp.help_doc = "Creates a Django app directory structure for the given app name in the current directory."
startapp.args = "[appname]"

def inspectdb():
    "Generator that introspects the tables in the given database name and returns a Django model, one line at a time."
    from django.db import connection, get_introspection_module
    import keyword

    introspection_module = get_introspection_module()

    table2model = lambda table_name: table_name.title().replace('_', '')

    cursor = connection.cursor()
    yield "# This is an auto-generated Django model module."
    yield "# You'll have to do the following manually to clean this up:"
    yield "#     * Rearrange models' order"
    yield "#     * Make sure each model has one field with primary_key=True"
    yield "# Feel free to rename the models, but don't rename db_table values or field names."
    yield "#"
    yield "# Also note: You'll have to insert the output of 'django-admin.py sqlcustom [appname]'"
    yield "# into your database."
    yield ''
    yield 'from django.db import models'
    yield ''
    for table_name in introspection_module.get_table_list(cursor):
        yield 'class %s(models.Model):' % table2model(table_name)
        try:
            relations = introspection_module.get_relations(cursor, table_name)
        except NotImplementedError:
            relations = {}
        try:
            indexes = introspection_module.get_indexes(cursor, table_name)
        except NotImplementedError:
            indexes = {}
        for i, row in enumerate(introspection_module.get_table_description(cursor, table_name)):
            att_name = row[0].lower()
            comment_notes = [] # Holds Field notes, to be displayed in a Python comment.
            extra_params = {}  # Holds Field parameters such as 'db_column'.

            if ' ' in att_name:
                extra_params['db_column'] = att_name
                att_name = att_name.replace(' ', '')
                comment_notes.append('Field renamed to remove spaces.')
            if keyword.iskeyword(att_name):
                extra_params['db_column'] = att_name
                att_name += '_field'
                comment_notes.append('Field renamed because it was a Python reserved word.')

            if i in relations:
                rel_to = relations[i][1] == table_name and "'self'" or table2model(relations[i][1])
                field_type = 'ForeignKey(%s' % rel_to
                if att_name.endswith('_id'):
                    att_name = att_name[:-3]
                else:
                    extra_params['db_column'] = att_name
            else:
                try:
                    field_type = introspection_module.DATA_TYPES_REVERSE[row[1]]
                except KeyError:
                    field_type = 'TextField'
                    comment_notes.append('This field type is a guess.')

                # This is a hook for DATA_TYPES_REVERSE to return a tuple of
                # (field_type, extra_params_dict).
                if type(field_type) is tuple:
                    field_type, new_params = field_type
                    extra_params.update(new_params)

                # Add maxlength for all CharFields.
                if field_type == 'CharField' and row[3]:
                    extra_params['maxlength'] = row[3]

                if field_type == 'DecimalField':
                    extra_params['max_digits'] = row[4]
                    extra_params['decimal_places'] = row[5]

                # Add primary_key and unique, if necessary.
                column_name = extra_params.get('db_column', att_name)
                if column_name in indexes:
                    if indexes[column_name]['primary_key']:
                        extra_params['primary_key'] = True
                    elif indexes[column_name]['unique']:
                        extra_params['unique'] = True

                field_type += '('

            # Don't output 'id = meta.AutoField(primary_key=True)', because
            # that's assumed if it doesn't exist.
            if att_name == 'id' and field_type == 'AutoField(' and extra_params == {'primary_key': True}:
                continue

            # Add 'null' and 'blank', if the 'null_ok' flag was present in the
            # table description.
            if row[6]: # If it's NULL...
                extra_params['blank'] = True
                if not field_type in ('TextField(', 'CharField('):
                    extra_params['null'] = True

            field_desc = '%s = models.%s' % (att_name, field_type)
            if extra_params:
                if not field_desc.endswith('('):
                    field_desc += ', '
                field_desc += ', '.join(['%s=%r' % (k, v) for k, v in extra_params.items()])
            field_desc += ')'
            if comment_notes:
                field_desc += ' # ' + ' '.join(comment_notes)
            yield '    %s' % field_desc
        yield '    class Meta:'
        yield '        db_table = %r' % table_name
        yield ''
inspectdb.help_doc = "Introspects the database tables in the given database and outputs a Django model module."
inspectdb.args = ""

class ModelErrorCollection:
    def __init__(self, outfile=sys.stdout):
        self.errors = []
        self.outfile = outfile

    def add(self, context, error):
        self.errors.append((context, error))
        self.outfile.write(style.ERROR("%s: %s\n" % (context, error)))

def get_validation_errors(outfile, app=None):
    """
    Validates all models that are part of the specified app. If no app name is provided,
    validates all models of all installed apps. Writes errors, if any, to outfile.
    Returns number of errors.
    """
    from django.conf import settings
    from django.db import models, connection
    from django.db.models.loading import get_app_errors
    from django.db.models.fields.related import RelatedObject

    e = ModelErrorCollection(outfile)

    for (app_name, error) in get_app_errors().items():
        e.add(app_name, error)

    for cls in models.get_models(app):
        opts = cls._meta

        # Do field-specific validation.
        for f in opts.fields:
            if f.name == 'id' and not f.primary_key and opts.pk.name == 'id':
                e.add(opts, '"%s": You can\'t use "id" as a field name, because each model automatically gets an "id" field if none of the fields have primary_key=True. You need to either remove/rename your "id" field or add primary_key=True to a field.' % f.name)
            if isinstance(f, models.CharField) and f.maxlength in (None, 0):
                e.add(opts, '"%s": CharFields require a "maxlength" attribute.' % f.name)
            if isinstance(f, models.DecimalField):
                if f.decimal_places is None:
                    e.add(opts, '"%s": DecimalFields require a "decimal_places" attribute.' % f.name)
                if f.max_digits is None:
                    e.add(opts, '"%s": DecimalFields require a "max_digits" attribute.' % f.name)
            if isinstance(f, models.FileField) and not f.upload_to:
                e.add(opts, '"%s": FileFields require an "upload_to" attribute.' % f.name)
            if isinstance(f, models.ImageField):
                try:
                    from PIL import Image
                except ImportError:
                    e.add(opts, '"%s": To use ImageFields, you need to install the Python Imaging Library. Get it at http://www.pythonware.com/products/pil/ .' % f.name)
            if f.prepopulate_from is not None and type(f.prepopulate_from) not in (list, tuple):
                e.add(opts, '"%s": prepopulate_from should be a list or tuple.' % f.name)
            if f.choices:
                if not hasattr(f.choices, '__iter__'):
                    e.add(opts, '"%s": "choices" should be iterable (e.g., a tuple or list).' % f.name)
                else:
                    for c in f.choices:
                        if not type(c) in (tuple, list) or len(c) != 2:
                            e.add(opts, '"%s": "choices" should be a sequence of two-tuples.' % f.name)
            if f.db_index not in (None, True, False):
                e.add(opts, '"%s": "db_index" should be either None, True or False.' % f.name)

            # Check that maxlength <= 255 if using older MySQL versions.
            if settings.DATABASE_ENGINE == 'mysql':
                db_version = connection.get_server_version()
                if db_version < (5, 0, 3) and isinstance(f, (models.CharField, models.CommaSeparatedIntegerField, models.SlugField)) and f.maxlength > 255:
                    e.add(opts, '"%s": %s cannot have a "maxlength" greater than 255 when you are using a version of MySQL prior to 5.0.3 (you are using %s).' % (f.name, f.__class__.__name__, '.'.join([str(n) for n in db_version[:3]])))

            # Check to see if the related field will clash with any
            # existing fields, m2m fields, m2m related objects or related objects
            if f.rel:
                rel_opts = f.rel.to._meta
                if f.rel.to not in models.get_models():
                    e.add(opts, "'%s' has relation with model %s, which has not been installed" % (f.name, rel_opts.object_name))

                rel_name = RelatedObject(f.rel.to, cls, f).get_accessor_name()
                rel_query_name = f.related_query_name()
                for r in rel_opts.fields:
                    if r.name == rel_name:
                        e.add(opts, "Accessor for field '%s' clashes with field '%s.%s'. Add a related_name argument to the definition for '%s'." % (f.name, rel_opts.object_name, r.name, f.name))
                    if r.name == rel_query_name:
                        e.add(opts, "Reverse query name for field '%s' clashes with field '%s.%s'. Add a related_name argument to the definition for '%s'." % (f.name, rel_opts.object_name, r.name, f.name))
                for r in rel_opts.many_to_many:
                    if r.name == rel_name:
                        e.add(opts, "Accessor for field '%s' clashes with m2m field '%s.%s'. Add a related_name argument to the definition for '%s'." % (f.name, rel_opts.object_name, r.name, f.name))
                    if r.name == rel_query_name:
                        e.add(opts, "Reverse query name for field '%s' clashes with m2m field '%s.%s'. Add a related_name argument to the definition for '%s'." % (f.name, rel_opts.object_name, r.name, f.name))
                for r in rel_opts.get_all_related_many_to_many_objects():
                    if r.get_accessor_name() == rel_name:
                        e.add(opts, "Accessor for field '%s' clashes with related m2m field '%s.%s'. Add a related_name argument to the definition for '%s'." % (f.name, rel_opts.object_name, r.get_accessor_name(), f.name))
                    if r.get_accessor_name() == rel_query_name:
                        e.add(opts, "Reverse query name for field '%s' clashes with related m2m field '%s.%s'. Add a related_name argument to the definition for '%s'." % (f.name, rel_opts.object_name, r.get_accessor_name(), f.name))
                for r in rel_opts.get_all_related_objects():
                    if r.field is not f:
                        if r.get_accessor_name() == rel_name:
                            e.add(opts, "Accessor for field '%s' clashes with related field '%s.%s'. Add a related_name argument to the definition for '%s'." % (f.name, rel_opts.object_name, r.get_accessor_name(), f.name))
                        if r.get_accessor_name() == rel_query_name:
                            e.add(opts, "Reverse query name for field '%s' clashes with related field '%s.%s'. Add a related_name argument to the definition for '%s'." % (f.name, rel_opts.object_name, r.get_accessor_name(), f.name))


        for i, f in enumerate(opts.many_to_many):
            # Check to see if the related m2m field will clash with any
            # existing fields, m2m fields, m2m related objects or related objects
            rel_opts = f.rel.to._meta
            if f.rel.to not in models.get_models():
                e.add(opts, "'%s' has m2m relation with model %s, which has not been installed" % (f.name, rel_opts.object_name))

            rel_name = RelatedObject(f.rel.to, cls, f).get_accessor_name()
            rel_query_name = f.related_query_name()
            # If rel_name is none, there is no reverse accessor.
            # (This only occurs for symmetrical m2m relations to self).
            # If this is the case, there are no clashes to check for this field, as
            # there are no reverse descriptors for this field.
            if rel_name is not None:
                for r in rel_opts.fields:
                    if r.name == rel_name:
                        e.add(opts, "Accessor for m2m field '%s' clashes with field '%s.%s'. Add a related_name argument to the definition for '%s'." % (f.name, rel_opts.object_name, r.name, f.name))
                    if r.name == rel_query_name:
                        e.add(opts, "Reverse query name for m2m field '%s' clashes with field '%s.%s'. Add a related_name argument to the definition for '%s'." % (f.name, rel_opts.object_name, r.name, f.name))
                for r in rel_opts.many_to_many:
                    if r.name == rel_name:
                        e.add(opts, "Accessor for m2m field '%s' clashes with m2m field '%s.%s'. Add a related_name argument to the definition for '%s'." % (f.name, rel_opts.object_name, r.name, f.name))
                    if r.name == rel_query_name:
                        e.add(opts, "Reverse query name for m2m field '%s' clashes with m2m field '%s.%s'. Add a related_name argument to the definition for '%s'." % (f.name, rel_opts.object_name, r.name, f.name))
                for r in rel_opts.get_all_related_many_to_many_objects():
                    if r.field is not f:
                        if r.get_accessor_name() == rel_name:
                            e.add(opts, "Accessor for m2m field '%s' clashes with related m2m field '%s.%s'. Add a related_name argument to the definition for '%s'." % (f.name, rel_opts.object_name, r.get_accessor_name(), f.name))
                        if r.get_accessor_name() == rel_query_name:
                            e.add(opts, "Reverse query name for m2m field '%s' clashes with related m2m field '%s.%s'. Add a related_name argument to the definition for '%s'." % (f.name, rel_opts.object_name, r.get_accessor_name(), f.name))
                for r in rel_opts.get_all_related_objects():
                    if r.get_accessor_name() == rel_name:
                        e.add(opts, "Accessor for m2m field '%s' clashes with related field '%s.%s'. Add a related_name argument to the definition for '%s'." % (f.name, rel_opts.object_name, r.get_accessor_name(), f.name))
                    if r.get_accessor_name() == rel_query_name:
                        e.add(opts, "Reverse query name for m2m field '%s' clashes with related field '%s.%s'. Add a related_name argument to the definition for '%s'." % (f.name, rel_opts.object_name, r.get_accessor_name(), f.name))

        # Check admin attribute.
        if opts.admin is not None:
            if not isinstance(opts.admin, models.AdminOptions):
                e.add(opts, '"admin" attribute, if given, must be set to a models.AdminOptions() instance.')
            else:
                # list_display
                if not isinstance(opts.admin.list_display, (list, tuple)):
                    e.add(opts, '"admin.list_display", if given, must be set to a list or tuple.')
                else:
                    for fn in opts.admin.list_display:
                        try:
                            f = opts.get_field(fn)
                        except models.FieldDoesNotExist:
                            if not hasattr(cls, fn):
                                e.add(opts, '"admin.list_display" refers to %r, which isn\'t an attribute, method or property.' % fn)
                        else:
                            if isinstance(f, models.ManyToManyField):
                                e.add(opts, '"admin.list_display" doesn\'t support ManyToManyFields (%r).' % fn)
                # list_display_links
                if opts.admin.list_display_links and not opts.admin.list_display:
                    e.add(opts, '"admin.list_display" must be defined for "admin.list_display_links" to be used.')
                if not isinstance(opts.admin.list_display_links, (list, tuple)):
                    e.add(opts, '"admin.list_display_links", if given, must be set to a list or tuple.')
                else:
                    for fn in opts.admin.list_display_links:
                        try:
                            f = opts.get_field(fn)
                        except models.FieldDoesNotExist:
                            if not hasattr(cls, fn):
                                e.add(opts, '"admin.list_display_links" refers to %r, which isn\'t an attribute, method or property.' % fn)
                        if fn not in opts.admin.list_display:
                            e.add(opts, '"admin.list_display_links" refers to %r, which is not defined in "admin.list_display".' % fn)
                # list_filter
                if not isinstance(opts.admin.list_filter, (list, tuple)):
                    e.add(opts, '"admin.list_filter", if given, must be set to a list or tuple.')
                else:
                    for fn in opts.admin.list_filter:
                        try:
                            f = opts.get_field(fn)
                        except models.FieldDoesNotExist:
                            e.add(opts, '"admin.list_filter" refers to %r, which isn\'t a field.' % fn)
                # date_hierarchy
                if opts.admin.date_hierarchy:
                    try:
                        f = opts.get_field(opts.admin.date_hierarchy)
                    except models.FieldDoesNotExist:
                        e.add(opts, '"admin.date_hierarchy" refers to %r, which isn\'t a field.' % opts.admin.date_hierarchy)

        # Check ordering attribute.
        if opts.ordering:
            for field_name in opts.ordering:
                if field_name == '?': continue
                if field_name.startswith('-'):
                    field_name = field_name[1:]
                if opts.order_with_respect_to and field_name == '_order':
                    continue
                if '.' in field_name: continue # Skip ordering in the format 'table.field'.
                try:
                    opts.get_field(field_name, many_to_many=False)
                except models.FieldDoesNotExist:
                    e.add(opts, '"ordering" refers to "%s", a field that doesn\'t exist.' % field_name)

        # Check core=True, if needed.
        for related in opts.get_followed_related_objects():
            if not related.edit_inline:
                continue
            try:
                for f in related.opts.fields:
                    if f.core:
                        raise StopIteration
                e.add(related.opts, "At least one field in %s should have core=True, because it's being edited inline by %s.%s." % (related.opts.object_name, opts.module_name, opts.object_name))
            except StopIteration:
                pass

        # Check unique_together.
        for ut in opts.unique_together:
            for field_name in ut:
                try:
                    f = opts.get_field(field_name, many_to_many=True)
                except models.FieldDoesNotExist:
                    e.add(opts, '"unique_together" refers to %s, a field that doesn\'t exist. Check your syntax.' % field_name)
                else:
                    if isinstance(f.rel, models.ManyToManyRel):
                        e.add(opts, '"unique_together" refers to %s. ManyToManyFields are not supported in unique_together.' % f.name)

    return len(e.errors)

def validate(outfile=sys.stdout, silent_success=False):
    "Validates all installed models."
    try:
        num_errors = get_validation_errors(outfile)
        if silent_success and num_errors == 0:
            return
        outfile.write('%s error%s found.\n' % (num_errors, num_errors != 1 and 's' or ''))
    except ImproperlyConfigured:
        outfile.write("Skipping validation because things aren't configured properly.\n")
validate.args = ''

def _check_for_validation_errors(app=None):
    """Check that an app has no validation errors, and exit with errors if it does."""
    try:
        from cStringIO import StringIO
    except ImportError:
        from StringIO import StringIO
    s = StringIO()
    num_errors = get_validation_errors(s, app)
    if num_errors:
        if app:
            sys.stderr.write(style.ERROR("Error: %s couldn't be installed, because there were errors in your model:\n" % app))
        else:
            sys.stderr.write(style.ERROR("Error: Couldn't install apps, because there were errors in one or more models:\n"))
        s.seek(0)
        sys.stderr.write(s.read())
        sys.exit(1)

def runserver(addr, port, use_reloader=True, admin_media_dir=''):
    "Starts a lightweight Web server for development."
    from django.core.servers.basehttp import run, AdminMediaHandler, WSGIServerException
    from django.core.handlers.wsgi import WSGIHandler
    if not addr:
        addr = '127.0.0.1'
    if not port.isdigit():
        sys.stderr.write(style.ERROR("Error: %r is not a valid port number.\n" % port))
        sys.exit(1)
    quit_command = sys.platform == 'win32' and 'CTRL-BREAK' or 'CONTROL-C'
    def inner_run():
        from django.conf import settings
        print "Validating models..."
        validate()
        print "\nDjango version %s, using settings %r" % (get_version(), settings.SETTINGS_MODULE)
        print "Development server is running at http://%s:%s/" % (addr, port)
        print "Quit the server with %s." % quit_command
        try:
            import django
            path = admin_media_dir or django.__path__[0] + '/contrib/admin/media'
            handler = AdminMediaHandler(WSGIHandler(), path)
            run(addr, int(port), handler)
        except WSGIServerException, e:
            # Use helpful error messages instead of ugly tracebacks.
            ERRORS = {
                13: "You don't have permission to access that port.",
                98: "That port is already in use.",
                99: "That IP address can't be assigned-to.",
            }
            try:
                error_text = ERRORS[e.args[0].args[0]]
            except (AttributeError, KeyError):
                error_text = str(e)
            sys.stderr.write(style.ERROR("Error: %s" % error_text) + '\n')
            sys.exit(1)
        except KeyboardInterrupt:
            sys.exit(0)
    if use_reloader:
        from django.utils import autoreload
        autoreload.main(inner_run)
    else:
        inner_run()
runserver.args = '[--noreload] [--adminmedia=ADMIN_MEDIA_PATH] [optional port number, or ipaddr:port]'

def createcachetable(tablename):
    "Creates the table needed to use the SQL cache backend"
    from django.db import backend, connection, transaction, models
    fields = (
        # "key" is a reserved word in MySQL, so use "cache_key" instead.
        models.CharField(name='cache_key', maxlength=255, unique=True, primary_key=True),
        models.TextField(name='value'),
        models.DateTimeField(name='expires', db_index=True),
    )
    table_output = []
    index_output = []
    for f in fields:
        field_output = [backend.quote_name(f.name), f.db_type()]
        field_output.append("%sNULL" % (not f.null and "NOT " or ""))
        if f.unique:
            field_output.append("UNIQUE")
        if f.primary_key:
            field_output.append("PRIMARY KEY")
        if f.db_index:
            unique = f.unique and "UNIQUE " or ""
            index_output.append("CREATE %sINDEX %s_%s ON %s (%s);" % \
                (unique, tablename, f.name, backend.quote_name(tablename),
                backend.quote_name(f.name)))
        table_output.append(" ".join(field_output))
    full_statement = ["CREATE TABLE %s (" % backend.quote_name(tablename)]
    for i, line in enumerate(table_output):
        full_statement.append('    %s%s' % (line, i < len(table_output)-1 and ',' or ''))
    full_statement.append(');')
    curs = connection.cursor()
    curs.execute("\n".join(full_statement))
    for statement in index_output:
        curs.execute(statement)
    transaction.commit_unless_managed()
createcachetable.args = "[tablename]"

def run_shell(use_plain=False):
    "Runs a Python interactive interpreter. Tries to use IPython, if it's available."
    # XXX: (Temporary) workaround for ticket #1796: force early loading of all
    # models from installed apps.
    from django.db.models.loading import get_models
    loaded_models = get_models()

    try:
        if use_plain:
            # Don't bother loading IPython, because the user wants plain Python.
            raise ImportError
        import IPython
        # Explicitly pass an empty list as arguments, because otherwise IPython
        # would use sys.argv from this script.
        shell = IPython.Shell.IPShell(argv=[])
        shell.mainloop()
    except ImportError:
        import code
        try: # Try activating rlcompleter, because it's handy.
            import readline
        except ImportError:
            pass
        else:
            # We don't have to wrap the following import in a 'try', because
            # we already know 'readline' was imported successfully.
            import rlcompleter
            readline.parse_and_bind("tab:complete")
        code.interact()
run_shell.args = '[--plain]'

def dbshell():
    "Runs the command-line client for the current DATABASE_ENGINE."
    from django.db import runshell
    runshell()
dbshell.args = ""

def runfcgi(args):
    "Runs this project as a FastCGI application. Requires flup."
    from django.conf import settings
    from django.utils import translation
    # Activate the current language, because it won't get activated later.
    try:
        translation.activate(settings.LANGUAGE_CODE)
    except AttributeError:
        pass
    from django.core.servers.fastcgi import runfastcgi
    runfastcgi(args)
runfcgi.args = '[various KEY=val options, use `runfcgi help` for help]'

def test(app_labels, verbosity=1):
    "Runs the test suite for the specified applications"
    from django.conf import settings
    from django.db.models import get_app, get_apps

    if len(app_labels) == 0:
        app_list = get_apps()
    else:
        app_list = [get_app(app_label) for app_label in app_labels]

    test_path = settings.TEST_RUNNER.split('.')
    # Allow for Python 2.5 relative paths
    if len(test_path) > 1:
        test_module_name = '.'.join(test_path[:-1])
    else:
        test_module_name = '.'
    test_module = __import__(test_module_name, {}, {}, test_path[-1])
    test_runner = getattr(test_module, test_path[-1])

    failures = test_runner(app_list, verbosity)
    if failures:
        sys.exit(failures)

test.help_doc = 'Runs the test suite for the specified applications, or the entire site if no apps are specified'
test.args = '[--verbosity] ' + APP_ARGS

def load_data(fixture_labels, verbosity=1):
    "Installs the provided fixture file(s) as data in the database."
    from django.db.models import get_apps
    from django.core import serializers
    from django.db import connection, transaction, backend
    from django.conf import settings
    import sys

    disable_termcolors()

    # Keep a count of the installed objects and fixtures
    count = [0,0]
    models = set()

    humanize = lambda dirname: dirname and "'%s'" % dirname or 'absolute path'

    # Get a cursor (even though we don't need one yet). This has
    # the side effect of initializing the test database (if
    # it isn't already initialized).
    cursor = connection.cursor()

    # Start transaction management. All fixtures are installed in a
    # single transaction to ensure that all references are resolved.
    transaction.commit_unless_managed()
    transaction.enter_transaction_management()
    transaction.managed(True)

    app_fixtures = [os.path.join(os.path.dirname(app.__file__),'fixtures') for app in get_apps()]
    for fixture_label in fixture_labels:
        parts = fixture_label.split('.')
        if len(parts) == 1:
            fixture_name = fixture_label
            formats = serializers.get_serializer_formats()
        else:
            fixture_name, format = '.'.join(parts[:-1]), parts[-1]
            if format in serializers.get_serializer_formats():
                formats = [format]
            else:
                formats = []

        if verbosity > 0:
            if formats:
                print "Loading '%s' fixtures..." % fixture_name
            else:
                print "Skipping fixture '%s': %s is not a known serialization format" % (fixture_name, format)

        for fixture_dir in app_fixtures + list(settings.FIXTURE_DIRS) + ['']:
            if verbosity > 1:
                print "Checking %s for fixtures..." % humanize(fixture_dir)

            label_found = False
            for format in formats:
                serializer = serializers.get_serializer(format)
                if verbosity > 1:
                    print "Trying %s for %s fixture '%s'..." % \
                        (humanize(fixture_dir), format, fixture_name)
                try:
                    full_path = os.path.join(fixture_dir, '.'.join([fixture_name, format]))
                    fixture = open(full_path, 'r')
                    if label_found:
                        fixture.close()
                        print style.ERROR("Multiple fixtures named '%s' in %s. Aborting." %
                            (fixture_name, humanize(fixture_dir)))
                        transaction.rollback()
                        transaction.leave_transaction_management()
                        return
                    else:
                        count[1] += 1
                        if verbosity > 0:
                            print "Installing %s fixture '%s' from %s." % \
                                (format, fixture_name, humanize(fixture_dir))
                        try:
                            objects =  serializers.deserialize(format, fixture)
                            for obj in objects:
                                count[0] += 1
                                models.add(obj.object.__class__)
                                obj.save()
                            label_found = True
                        except Exception, e:
                            fixture.close()
                            sys.stderr.write(
                                style.ERROR("Problem installing fixture '%s': %s\n" %
                                     (full_path, str(e))))
                            transaction.rollback()
                            transaction.leave_transaction_management()
                            return
                        fixture.close()
                except:
                    if verbosity > 1:
                        print "No %s fixture '%s' in %s." % \
                            (format, fixture_name, humanize(fixture_dir))

    if count[0] > 0:
        sequence_sql = backend.get_sql_sequence_reset(style, models)
        if sequence_sql:
            if verbosity > 1:
                print "Resetting sequences"
            for line in sequence_sql:
                cursor.execute(line)

    transaction.commit()
    transaction.leave_transaction_management()

    if count[0] == 0:
        if verbosity > 0:
            print "No fixtures found."
    else:
        if verbosity > 0:
            print "Installed %d object(s) from %d fixture(s)" % tuple(count)

load_data.help_doc = 'Installs the named fixture(s) in the database'
load_data.args = "[--verbosity] fixture, fixture, ..."

def dump_data(app_labels, format='json', indent=None):
    "Output the current contents of the database as a fixture of the given format"
    from django.db.models import get_app, get_apps, get_models
    from django.core import serializers

    if len(app_labels) == 0:
        app_list = get_apps()
    else:
        app_list = [get_app(app_label) for app_label in app_labels]

    # Check that the serialization format exists; this is a shortcut to
    # avoid collating all the objects and _then_ failing.
    try:
        serializers.get_serializer(format)
    except KeyError:
        sys.stderr.write(style.ERROR("Unknown serialization format: %s\n" % format))

    objects = []
    for app in app_list:
        for model in get_models(app):
            objects.extend(model.objects.all())
    try:
        return serializers.serialize(format, objects, indent=indent)
    except Exception, e:
        sys.stderr.write(style.ERROR("Unable to serialize database: %s\n" % e))
dump_data.help_doc = 'Output the contents of the database as a fixture of the given format'
dump_data.args = '[--format] [--indent]' + APP_ARGS

# Utilities for command-line script

DEFAULT_ACTION_MAPPING = {
    'adminindex': get_admin_index,
    'createcachetable' : createcachetable,
    'dbshell': dbshell,
    'diffsettings': diffsettings,
    'dumpdata': dump_data,
    'flush': flush,
    'inspectdb': inspectdb,
    'loaddata': load_data,
    'reset': reset,
    'runfcgi': runfcgi,
    'runserver': runserver,
    'shell': run_shell,
    'sql': get_sql_create,
    'sqlall': get_sql_all,
    'sqlclear': get_sql_delete,
    'sqlcustom': get_custom_sql,
    'sqlflush': get_sql_flush,
    'sqlindexes': get_sql_indexes,
    'sqlinitialdata': get_sql_initial_data,
    'sqlreset': get_sql_reset,
    'sqlsequencereset': get_sql_sequence_reset,
    'sqlevolve': get_sql_evolution,
    'startapp': startapp,
    'startproject': startproject,
    'syncdb': syncdb,
    'validate': validate,
    'test':test,
}

NO_SQL_TRANSACTION = (
    'adminindex',
    'createcachetable',
    'dbshell',
    'diffsettings',
    'reset',
    'sqlindexes',
    'syncdb',
)

class DjangoOptionParser(OptionParser):
    def print_usage_and_exit(self):
        self.print_help(sys.stderr)
        sys.exit(1)

def get_usage(action_mapping):
    """
    Returns a usage string. Doesn't do the options stuff, because optparse
    takes care of that.
    """
    usage = ["%prog action [options]\nactions:"]
    available_actions = action_mapping.keys()
    available_actions.sort()
    for a in available_actions:
        func = action_mapping[a]
        usage.append("  %s %s" % (a, func.args))
        usage.extend(textwrap.wrap(getattr(func, 'help_doc', textwrap.dedent(func.__doc__.strip())), initial_indent='    ', subsequent_indent='    '))
        usage.append("")
    return '\n'.join(usage[:-1]) # Cut off last list element, an empty space.

def print_error(msg, cmd):
    sys.stderr.write(style.ERROR('Error: %s' % msg) + '\nRun "%s --help" for help.\n' % cmd)
    sys.exit(1)

def execute_from_command_line(action_mapping=DEFAULT_ACTION_MAPPING, argv=None):
    # Use sys.argv if we've not passed in a custom argv
    if argv is None:
        argv = sys.argv

    # Parse the command-line arguments. optparse handles the dirty work.
    parser = DjangoOptionParser(usage=get_usage(action_mapping), version=get_version())
    parser.add_option('--settings',
        help='Python path to settings module, e.g. "myproject.settings.main". If this isn\'t provided, the DJANGO_SETTINGS_MODULE environment variable will be used.')
    parser.add_option('--pythonpath',
        help='Lets you manually add a directory the Python path, e.g. "/home/djangoprojects/myproject".')
    parser.add_option('--plain', action='store_true', dest='plain',
        help='Tells Django to use plain Python, not IPython, for "shell" command.')
    parser.add_option('--noinput', action='store_false', dest='interactive', default=True,
        help='Tells Django to NOT prompt the user for input of any kind.')
    parser.add_option('--noreload', action='store_false', dest='use_reloader', default=True,
        help='Tells Django to NOT use the auto-reloader when running the development server.')
    parser.add_option('--format', default='json', dest='format',
        help='Specifies the output serialization format for fixtures')
    parser.add_option('--indent', default=None, dest='indent',
        type='int', help='Specifies the indent level to use when pretty-printing output')
    parser.add_option('--verbosity', action='store', dest='verbosity', default='1',
        type='choice', choices=['0', '1', '2'],
        help='Verbosity level; 0=minimal output, 1=normal output, 2=all output'),
    parser.add_option('--adminmedia', dest='admin_media_path', default='', help='Specifies the directory from which to serve admin media for runserver.'),

    options, args = parser.parse_args(argv[1:])

    # Take care of options.
    if options.settings:
        os.environ['DJANGO_SETTINGS_MODULE'] = options.settings
    if options.pythonpath:
        sys.path.insert(0, options.pythonpath)

    # Run the appropriate action. Unfortunately, optparse can't handle
    # positional arguments, so this has to parse/validate them.
    try:
        action = args[0]
    except IndexError:
        parser.print_usage_and_exit()
    if action not in action_mapping:
        print_error("Your action, %r, was invalid." % action, argv[0])

    # Switch to English, because django-admin.py creates database content
    # like permissions, and those shouldn't contain any translations.
    # But only do this if we should have a working settings file.
    if action not in ('startproject', 'startapp'):
        from django.utils import translation
        translation.activate('en-us')

    if action == 'shell':
        action_mapping[action](options.plain is True)
    elif action in ('validate', 'diffsettings', 'dbshell'):
        action_mapping[action]()
    elif action in ('flush', 'syncdb'):
        action_mapping[action](int(options.verbosity), options.interactive)
    elif action == 'inspectdb':
        try:
            for line in action_mapping[action]():
                print line
        except NotImplementedError:
            sys.stderr.write(style.ERROR("Error: %r isn't supported for the currently selected database backend.\n" % action))
            sys.exit(1)
    elif action == 'createcachetable':
        try:
            action_mapping[action](args[1])
        except IndexError:
            parser.print_usage_and_exit()
    elif action in ('test', 'loaddata'):
        try:
            action_mapping[action](args[1:], int(options.verbosity))
        except IndexError:
            parser.print_usage_and_exit()
    elif action == 'dumpdata':
        try:
            print action_mapping[action](args[1:], options.format, options.indent)
        except IndexError:
            parser.print_usage_and_exit()
    elif action in ('startapp', 'startproject'):
        try:
            name = args[1]
        except IndexError:
            parser.print_usage_and_exit()
        action_mapping[action](name, os.getcwd())
    elif action == 'runserver':
        if len(args) < 2:
            addr = ''
            port = '8000'
        else:
            try:
                addr, port = args[1].split(':')
            except ValueError:
                addr, port = '', args[1]
        action_mapping[action](addr, port, options.use_reloader, options.admin_media_path)
    elif action == 'runfcgi':
        action_mapping[action](args[1:])
    elif action == 'sqlinitialdata':
        print action_mapping[action](args[1:])
    elif action == 'sqlflush':
        print '\n'.join(action_mapping[action]())
    else:
        from django.db import models
        validate(silent_success=True)
        try:
            mod_list = [models.get_app(app_label) for app_label in args[1:]]
        except ImportError, e:
            sys.stderr.write(style.ERROR("Error: %s. Are you sure your INSTALLED_APPS setting is correct?\n" % e))
            sys.exit(1)
        if not mod_list:
            parser.print_usage_and_exit()
        if action not in NO_SQL_TRANSACTION:
            from django.db import backend
            if backend.get_start_transaction_sql():
                print style.SQL_KEYWORD(backend.get_start_transaction_sql())
        for mod in mod_list:
            if action == 'reset':
                output = action_mapping[action](mod, options.interactive)
            else:
                output = action_mapping[action](mod)
            if output:
                print '\n'.join(output)
        if action not in NO_SQL_TRANSACTION:
            print style.SQL_KEYWORD("COMMIT;")

def setup_environ(settings_mod):
    """
    Configure the runtime environment. This can also be used by external
    scripts wanting to set up a similar environment to manage.py.
    """
    # Add this project to sys.path so that it's importable in the conventional
    # way. For example, if this file (manage.py) lives in a directory
    # "myproject", this code would add "/path/to/myproject" to sys.path.
    project_directory, settings_filename = os.path.split(settings_mod.__file__)
    project_name = os.path.basename(project_directory)
    settings_name = os.path.splitext(settings_filename)[0]
    sys.path.append(os.path.join(project_directory, '..'))
    project_module = __import__(project_name, {}, {}, [''])
    sys.path.pop()

    # Set DJANGO_SETTINGS_MODULE appropriately.
    os.environ['DJANGO_SETTINGS_MODULE'] = '%s.%s' % (project_name, settings_name)
    return project_directory

def execute_manager(settings_mod, argv=None):
    project_directory = setup_environ(settings_mod)
    action_mapping = DEFAULT_ACTION_MAPPING.copy()

    # Remove the "startproject" command from the action_mapping, because that's
    # a django-admin.py command, not a manage.py command.
    del action_mapping['startproject']

    # Override the startapp handler so that it always uses the
    # project_directory, not the current working directory (which is default).
    action_mapping['startapp'] = lambda app_name, directory: startapp(app_name, project_directory)
    action_mapping['startapp'].__doc__ = startapp.__doc__
    action_mapping['startapp'].help_doc = startapp.help_doc
    action_mapping['startapp'].args = startapp.args

    # Run the django-admin.py command.
    execute_from_command_line(action_mapping, argv)