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"""
Database API
(part of web.py)
"""
__all__ = [
"UnknownParamstyle", "UnknownDB", "TransactionError",
"sqllist", "sqlors", "reparam", "sqlquote",
"SQLQuery", "SQLParam", "sqlparam",
"SQLLiteral", "sqlliteral",
"database", 'DB',
]
import time, os
try:
import datetime
except ImportError:
datetime = None
try: set
except NameError:
from sets import Set as set
from utils import threadeddict, storage, iters, iterbetter, safestr, safeunicode
try:
# db module can work independent of web.py
from webapi import debug, config
except:
import sys
debug = sys.stderr
config = storage()
class UnknownDB(Exception):
"""raised for unsupported dbms"""
pass
class _ItplError(ValueError):
def __init__(self, text, pos):
ValueError.__init__(self)
self.text = text
self.pos = pos
def __str__(self):
return "unfinished expression in %s at char %d" % (
repr(self.text), self.pos)
class TransactionError(Exception): pass
class UnknownParamstyle(Exception):
"""
raised for unsupported db paramstyles
(currently supported: qmark, numeric, format, pyformat)
"""
pass
class SQLParam(object):
"""
Parameter in SQLQuery.
>>> q = SQLQuery(["SELECT * FROM test WHERE name=", SQLParam("joe")])
>>> q
<sql: "SELECT * FROM test WHERE name='joe'">
>>> q.query()
'SELECT * FROM test WHERE name=%s'
>>> q.values()
['joe']
"""
__slots__ = ["value"]
def __init__(self, value):
self.value = value
def get_marker(self, paramstyle='pyformat'):
if paramstyle == 'qmark':
return '?'
elif paramstyle == 'numeric':
return ':1'
elif paramstyle is None or paramstyle in ['format', 'pyformat']:
return '%s'
raise UnknownParamstyle, paramstyle
def sqlquery(self):
return SQLQuery([self])
def __add__(self, other):
return self.sqlquery() + other
def __radd__(self, other):
return other + self.sqlquery()
def __str__(self):
return str(self.value)
def __repr__(self):
return '<param: %s>' % repr(self.value)
sqlparam = SQLParam
class SQLQuery(object):
"""
You can pass this sort of thing as a clause in any db function.
Otherwise, you can pass a dictionary to the keyword argument `vars`
and the function will call reparam for you.
Internally, consists of `items`, which is a list of strings and
SQLParams, which get concatenated to produce the actual query.
"""
__slots__ = ["items"]
# tested in sqlquote's docstring
def __init__(self, items=None):
r"""Creates a new SQLQuery.
>>> SQLQuery("x")
<sql: 'x'>
>>> q = SQLQuery(['SELECT * FROM ', 'test', ' WHERE x=', SQLParam(1)])
>>> q
<sql: 'SELECT * FROM test WHERE x=1'>
>>> q.query(), q.values()
('SELECT * FROM test WHERE x=%s', [1])
>>> SQLQuery(SQLParam(1))
<sql: '1'>
"""
if items is None:
self.items = []
elif isinstance(items, list):
self.items = items
elif isinstance(items, SQLParam):
self.items = [items]
elif isinstance(items, SQLQuery):
self.items = list(items.items)
else:
self.items = [items]
# Take care of SQLLiterals
for i, item in enumerate(self.items):
if isinstance(item, SQLParam) and isinstance(item.value, SQLLiteral):
self.items[i] = item.value.v
def append(self, value):
self.items.append(value)
def __add__(self, other):
if isinstance(other, basestring):
items = [other]
elif isinstance(other, SQLQuery):
items = other.items
else:
return NotImplemented
return SQLQuery(self.items + items)
def __radd__(self, other):
if isinstance(other, basestring):
items = [other]
else:
return NotImplemented
return SQLQuery(items + self.items)
def __iadd__(self, other):
if isinstance(other, (basestring, SQLParam)):
self.items.append(other)
elif isinstance(other, SQLQuery):
self.items.extend(other.items)
else:
return NotImplemented
return self
def __len__(self):
return len(self.query())
def query(self, paramstyle=None):
"""
Returns the query part of the sql query.
>>> q = SQLQuery(["SELECT * FROM test WHERE name=", SQLParam('joe')])
>>> q.query()
'SELECT * FROM test WHERE name=%s'
>>> q.query(paramstyle='qmark')
'SELECT * FROM test WHERE name=?'
"""
s = []
for x in self.items:
if isinstance(x, SQLParam):
x = x.get_marker(paramstyle)
s.append(safestr(x))
else:
x = safestr(x)
# automatically escape % characters in the query
# For backward compatability, ignore escaping when the query looks already escaped
if paramstyle in ['format', 'pyformat']:
if '%' in x and '%%' not in x:
x = x.replace('%', '%%')
s.append(x)
return "".join(s)
def values(self):
"""
Returns the values of the parameters used in the sql query.
>>> q = SQLQuery(["SELECT * FROM test WHERE name=", SQLParam('joe')])
>>> q.values()
['joe']
"""
return [i.value for i in self.items if isinstance(i, SQLParam)]
def join(items, sep=' ', prefix=None, suffix=None, target=None):
"""
Joins multiple queries.
>>> SQLQuery.join(['a', 'b'], ', ')
<sql: 'a, b'>
Optinally, prefix and suffix arguments can be provided.
>>> SQLQuery.join(['a', 'b'], ', ', prefix='(', suffix=')')
<sql: '(a, b)'>
If target argument is provided, the items are appended to target instead of creating a new SQLQuery.
"""
if target is None:
target = SQLQuery()
target_items = target.items
if prefix:
target_items.append(prefix)
for i, item in enumerate(items):
if i != 0:
target_items.append(sep)
if isinstance(item, SQLQuery):
target_items.extend(item.items)
else:
target_items.append(item)
if suffix:
target_items.append(suffix)
return target
join = staticmethod(join)
def _str(self):
try:
return self.query() % tuple([sqlify(x) for x in self.values()])
except (ValueError, TypeError):
return self.query()
def __str__(self):
return safestr(self._str())
def __unicode__(self):
return safeunicode(self._str())
def __repr__(self):
return '<sql: %s>' % repr(str(self))
class SQLLiteral:
"""
Protects a string from `sqlquote`.
>>> sqlquote('NOW()')
<sql: "'NOW()'">
>>> sqlquote(SQLLiteral('NOW()'))
<sql: 'NOW()'>
"""
def __init__(self, v):
self.v = v
def __repr__(self):
return self.v
sqlliteral = SQLLiteral
def _sqllist(values):
"""
>>> _sqllist([1, 2, 3])
<sql: '(1, 2, 3)'>
"""
items = []
items.append('(')
for i, v in enumerate(values):
if i != 0:
items.append(', ')
items.append(sqlparam(v))
items.append(')')
return SQLQuery(items)
def reparam(string_, dictionary):
"""
Takes a string and a dictionary and interpolates the string
using values from the dictionary. Returns an `SQLQuery` for the result.
>>> reparam("s = $s", dict(s=True))
<sql: "s = 't'">
>>> reparam("s IN $s", dict(s=[1, 2]))
<sql: 's IN (1, 2)'>
"""
dictionary = dictionary.copy() # eval mucks with it
vals = []
result = []
for live, chunk in _interpolate(string_):
if live:
v = eval(chunk, dictionary)
result.append(sqlquote(v))
else:
result.append(chunk)
return SQLQuery.join(result, '')
def sqlify(obj):
"""
converts `obj` to its proper SQL version
>>> sqlify(None)
'NULL'
>>> sqlify(True)
"'t'"
>>> sqlify(3)
'3'
"""
# because `1 == True and hash(1) == hash(True)`
# we have to do this the hard way...
if obj is None:
return 'NULL'
elif obj is True:
return "'t'"
elif obj is False:
return "'f'"
elif datetime and isinstance(obj, datetime.datetime):
return repr(obj.isoformat())
else:
if isinstance(obj, unicode): obj = obj.encode('utf8')
return repr(obj)
def sqllist(lst):
"""
Converts the arguments for use in something like a WHERE clause.
>>> sqllist(['a', 'b'])
'a, b'
>>> sqllist('a')
'a'
>>> sqllist(u'abc')
u'abc'
"""
if isinstance(lst, basestring):
return lst
else:
return ', '.join(lst)
def sqlors(left, lst):
"""
`left is a SQL clause like `tablename.arg = `
and `lst` is a list of values. Returns a reparam-style
pair featuring the SQL that ORs together the clause
for each item in the lst.
>>> sqlors('foo = ', [])
<sql: '1=2'>
>>> sqlors('foo = ', [1])
<sql: 'foo = 1'>
>>> sqlors('foo = ', 1)
<sql: 'foo = 1'>
>>> sqlors('foo = ', [1,2,3])
<sql: '(foo = 1 OR foo = 2 OR foo = 3 OR 1=2)'>
"""
if isinstance(lst, iters):
lst = list(lst)
ln = len(lst)
if ln == 0:
return SQLQuery("1=2")
if ln == 1:
lst = lst[0]
if isinstance(lst, iters):
return SQLQuery(['('] +
sum([[left, sqlparam(x), ' OR '] for x in lst], []) +
['1=2)']
)
else:
return left + sqlparam(lst)
def sqlwhere(dictionary, grouping=' AND '):
"""
Converts a `dictionary` to an SQL WHERE clause `SQLQuery`.
>>> sqlwhere({'cust_id': 2, 'order_id':3})
<sql: 'order_id = 3 AND cust_id = 2'>
>>> sqlwhere({'cust_id': 2, 'order_id':3}, grouping=', ')
<sql: 'order_id = 3, cust_id = 2'>
>>> sqlwhere({'a': 'a', 'b': 'b'}).query()
'a = %s AND b = %s'
"""
return SQLQuery.join([k + ' = ' + sqlparam(v) for k, v in dictionary.items()], grouping)
def sqlquote(a):
"""
Ensures `a` is quoted properly for use in a SQL query.
>>> 'WHERE x = ' + sqlquote(True) + ' AND y = ' + sqlquote(3)
<sql: "WHERE x = 't' AND y = 3">
>>> 'WHERE x = ' + sqlquote(True) + ' AND y IN ' + sqlquote([2, 3])
<sql: "WHERE x = 't' AND y IN (2, 3)">
"""
if isinstance(a, list):
return _sqllist(a)
else:
return sqlparam(a).sqlquery()
class Transaction:
"""Database transaction."""
def __init__(self, ctx):
self.ctx = ctx
self.transaction_count = transaction_count = len(ctx.transactions)
class transaction_engine:
"""Transaction Engine used in top level transactions."""
def do_transact(self):
ctx.commit(unload=False)
def do_commit(self):
ctx.commit()
def do_rollback(self):
ctx.rollback()
class subtransaction_engine:
"""Transaction Engine used in sub transactions."""
def query(self, q):
db_cursor = ctx.db.cursor()
ctx.db_execute(db_cursor, SQLQuery(q % transaction_count))
def do_transact(self):
self.query('SAVEPOINT webpy_sp_%s')
def do_commit(self):
self.query('RELEASE SAVEPOINT webpy_sp_%s')
def do_rollback(self):
self.query('ROLLBACK TO SAVEPOINT webpy_sp_%s')
class dummy_engine:
"""Transaction Engine used instead of subtransaction_engine
when sub transactions are not supported."""
do_transact = do_commit = do_rollback = lambda self: None
if self.transaction_count:
# nested transactions are not supported in some databases
if self.ctx.get('ignore_nested_transactions'):
self.engine = dummy_engine()
else:
self.engine = subtransaction_engine()
else:
self.engine = transaction_engine()
self.engine.do_transact()
self.ctx.transactions.append(self)
def __enter__(self):
return self
def __exit__(self, exctype, excvalue, traceback):
if exctype is not None:
self.rollback()
else:
self.commit()
def commit(self):
if len(self.ctx.transactions) > self.transaction_count:
self.engine.do_commit()
self.ctx.transactions = self.ctx.transactions[:self.transaction_count]
def rollback(self):
if len(self.ctx.transactions) > self.transaction_count:
self.engine.do_rollback()
self.ctx.transactions = self.ctx.transactions[:self.transaction_count]
class DB:
"""Database"""
def __init__(self, db_module, keywords):
"""Creates a database.
"""
# some DB implementaions take optional paramater `driver` to use a specific driver modue
# but it should not be passed to connect
keywords.pop('driver', None)
self.db_module = db_module
self.keywords = keywords
self._ctx = threadeddict()
# flag to enable/disable printing queries
self.printing = config.get('debug_sql', config.get('debug', False))
self.supports_multiple_insert = False
try:
import DBUtils
# enable pooling if DBUtils module is available.
self.has_pooling = True
except ImportError:
self.has_pooling = False
# Pooling can be disabled by passing pooling=False in the keywords.
self.has_pooling = self.keywords.pop('pooling', True) and self.has_pooling
def _getctx(self):
if not self._ctx.get('db'):
self._load_context(self._ctx)
return self._ctx
ctx = property(_getctx)
def _load_context(self, ctx):
ctx.dbq_count = 0
ctx.transactions = [] # stack of transactions
if self.has_pooling:
ctx.db = self._connect_with_pooling(self.keywords)
else:
ctx.db = self._connect(self.keywords)
ctx.db_execute = self._db_execute
if not hasattr(ctx.db, 'commit'):
ctx.db.commit = lambda: None
if not hasattr(ctx.db, 'rollback'):
ctx.db.rollback = lambda: None
def commit(unload=True):
# do db commit and release the connection if pooling is enabled.
ctx.db.commit()
if unload and self.has_pooling:
self._unload_context(self._ctx)
def rollback():
# do db rollback and release the connection if pooling is enabled.
ctx.db.rollback()
if self.has_pooling:
self._unload_context(self._ctx)
ctx.commit = commit
ctx.rollback = rollback
def _unload_context(self, ctx):
del ctx.db
def _connect(self, keywords):
return self.db_module.connect(**keywords)
def _connect_with_pooling(self, keywords):
def get_pooled_db():
from DBUtils import PooledDB
# In DBUtils 0.9.3, `dbapi` argument is renamed as `creator`
# see Bug#122112
if PooledDB.__version__.split('.') < '0.9.3'.split('.'):
return PooledDB.PooledDB(dbapi=self.db_module, **keywords)
else:
return PooledDB.PooledDB(creator=self.db_module, **keywords)
if getattr(self, '_pooleddb', None) is None:
self._pooleddb = get_pooled_db()
return self._pooleddb.connection()
def _db_cursor(self):
return self.ctx.db.cursor()
def _param_marker(self):
"""Returns parameter marker based on paramstyle attribute if this database."""
style = getattr(self, 'paramstyle', 'pyformat')
if style == 'qmark':
return '?'
elif style == 'numeric':
return ':1'
elif style in ['format', 'pyformat']:
return '%s'
raise UnknownParamstyle, style
def _db_execute(self, cur, sql_query):
"""executes an sql query"""
self.ctx.dbq_count += 1
try:
a = time.time()
query, params = self._process_query(sql_query)
out = cur.execute(query, params)
b = time.time()
except:
if self.printing:
print >> debug, 'ERR:', str(sql_query)
if self.ctx.transactions:
self.ctx.transactions[-1].rollback()
else:
self.ctx.rollback()
raise
if self.printing:
print >> debug, '%s (%s): %s' % (round(b-a, 2), self.ctx.dbq_count, str(sql_query))
return out
def _process_query(self, sql_query):
"""Takes the SQLQuery object and returns query string and parameters.
"""
paramstyle = getattr(self, 'paramstyle', 'pyformat')
query = sql_query.query(paramstyle)
params = sql_query.values()
return query, params
def _where(self, where, vars):
if isinstance(where, (int, long)):
where = "id = " + sqlparam(where)
#@@@ for backward-compatibility
elif isinstance(where, (list, tuple)) and len(where) == 2:
where = SQLQuery(where[0], where[1])
elif isinstance(where, SQLQuery):
pass
else:
where = reparam(where, vars)
return where
def query(self, sql_query, vars=None, processed=False, _test=False):
"""
Execute SQL query `sql_query` using dictionary `vars` to interpolate it.
If `processed=True`, `vars` is a `reparam`-style list to use
instead of interpolating.
>>> db = DB(None, {})
>>> db.query("SELECT * FROM foo", _test=True)
<sql: 'SELECT * FROM foo'>
>>> db.query("SELECT * FROM foo WHERE x = $x", vars=dict(x='f'), _test=True)
<sql: "SELECT * FROM foo WHERE x = 'f'">
>>> db.query("SELECT * FROM foo WHERE x = " + sqlquote('f'), _test=True)
<sql: "SELECT * FROM foo WHERE x = 'f'">
"""
if vars is None: vars = {}
if not processed and not isinstance(sql_query, SQLQuery):
sql_query = reparam(sql_query, vars)
if _test: return sql_query
db_cursor = self._db_cursor()
self._db_execute(db_cursor, sql_query)
if db_cursor.description:
names = [x[0] for x in db_cursor.description]
def iterwrapper():
row = db_cursor.fetchone()
while row:
yield storage(dict(zip(names, row)))
row = db_cursor.fetchone()
out = iterbetter(iterwrapper())
out.__len__ = lambda: int(db_cursor.rowcount)
out.list = lambda: [storage(dict(zip(names, x))) \
for x in db_cursor.fetchall()]
else:
out = db_cursor.rowcount
if not self.ctx.transactions:
self.ctx.commit()
return out
def select(self, tables, vars=None, what='*', where=None, order=None, group=None,
limit=None, offset=None, _test=False):
"""
Selects `what` from `tables` with clauses `where`, `order`,
`group`, `limit`, and `offset`. Uses vars to interpolate.
Otherwise, each clause can be a SQLQuery.
>>> db = DB(None, {})
>>> db.select('foo', _test=True)
<sql: 'SELECT * FROM foo'>
>>> db.select(['foo', 'bar'], where="foo.bar_id = bar.id", limit=5, _test=True)
<sql: 'SELECT * FROM foo, bar WHERE foo.bar_id = bar.id LIMIT 5'>
"""
if vars is None: vars = {}
sql_clauses = self.sql_clauses(what, tables, where, group, order, limit, offset)
clauses = [self.gen_clause(sql, val, vars) for sql, val in sql_clauses if val is not None]
qout = SQLQuery.join(clauses)
if _test: return qout
return self.query(qout, processed=True)
def where(self, table, what='*', order=None, group=None, limit=None,
offset=None, _test=False, **kwargs):
"""
Selects from `table` where keys are equal to values in `kwargs`.
>>> db = DB(None, {})
>>> db.where('foo', bar_id=3, _test=True)
<sql: 'SELECT * FROM foo WHERE bar_id = 3'>
>>> db.where('foo', source=2, crust='dewey', _test=True)
<sql: "SELECT * FROM foo WHERE source = 2 AND crust = 'dewey'">
>>> db.where('foo', _test=True)
<sql: 'SELECT * FROM foo'>
"""
where_clauses = []
for k, v in kwargs.iteritems():
where_clauses.append(k + ' = ' + sqlquote(v))
if where_clauses:
where = SQLQuery.join(where_clauses, " AND ")
else:
where = None
return self.select(table, what=what, order=order,
group=group, limit=limit, offset=offset, _test=_test,
where=where)
def sql_clauses(self, what, tables, where, group, order, limit, offset):
return (
('SELECT', what),
('FROM', sqllist(tables)),
('WHERE', where),
('GROUP BY', group),
('ORDER BY', order),
('LIMIT', limit),
('OFFSET', offset))
def gen_clause(self, sql, val, vars):
if isinstance(val, (int, long)):
if sql == 'WHERE':
nout = 'id = ' + sqlquote(val)
else:
nout = SQLQuery(val)
#@@@
elif isinstance(val, (list, tuple)) and len(val) == 2:
nout = SQLQuery(val[0], val[1]) # backwards-compatibility
elif isinstance(val, SQLQuery):
nout = val
else:
nout = reparam(val, vars)
def xjoin(a, b):
if a and b: return a + ' ' + b
else: return a or b
return xjoin(sql, nout)
def insert(self, tablename, seqname=None, _test=False, **values):
"""
Inserts `values` into `tablename`. Returns current sequence ID.
Set `seqname` to the ID if it's not the default, or to `False`
if there isn't one.
>>> db = DB(None, {})
>>> q = db.insert('foo', name='bob', age=2, created=SQLLiteral('NOW()'), _test=True)
>>> q
<sql: "INSERT INTO foo (age, name, created) VALUES (2, 'bob', NOW())">
>>> q.query()
'INSERT INTO foo (age, name, created) VALUES (%s, %s, NOW())'
>>> q.values()
[2, 'bob']
"""
def q(x): return "(" + x + ")"
if values:
_keys = SQLQuery.join(values.keys(), ', ')
_values = SQLQuery.join([sqlparam(v) for v in values.values()], ', ')
sql_query = "INSERT INTO %s " % tablename + q(_keys) + ' VALUES ' + q(_values)
else:
sql_query = SQLQuery(self._get_insert_default_values_query(tablename))
if _test: return sql_query
db_cursor = self._db_cursor()
if seqname is not False:
sql_query = self._process_insert_query(sql_query, tablename, seqname)
if isinstance(sql_query, tuple):
# for some databases, a separate query has to be made to find
# the id of the inserted row.
q1, q2 = sql_query
self._db_execute(db_cursor, q1)
self._db_execute(db_cursor, q2)
else:
self._db_execute(db_cursor, sql_query)
try:
out = db_cursor.fetchone()[0]
except Exception:
out = None
if not self.ctx.transactions:
self.ctx.commit()
return out
def _get_insert_default_values_query(self, table):
return "INSERT INTO %s DEFAULT VALUES" % table
def multiple_insert(self, tablename, values, seqname=None, _test=False):
"""
Inserts multiple rows into `tablename`. The `values` must be a list of dictioanries,
one for each row to be inserted, each with the same set of keys.
Returns the list of ids of the inserted rows.
Set `seqname` to the ID if it's not the default, or to `False`
if there isn't one.
>>> db = DB(None, {})
>>> db.supports_multiple_insert = True
>>> values = [{"name": "foo", "email": "foo@example.com"}, {"name": "bar", "email": "bar@example.com"}]
>>> db.multiple_insert('person', values=values, _test=True)
<sql: "INSERT INTO person (name, email) VALUES ('foo', 'foo@example.com'), ('bar', 'bar@example.com')">
"""
if not values:
return []
if not self.supports_multiple_insert:
out = [self.insert(tablename, seqname=seqname, _test=_test, **v) for v in values]
if seqname is False:
return None
else:
return out
keys = values[0].keys()
#@@ make sure all keys are valid
# make sure all rows have same keys.
for v in values:
if v.keys() != keys:
raise ValueError, 'Bad data'
sql_query = SQLQuery('INSERT INTO %s (%s) VALUES ' % (tablename, ', '.join(keys)))
for i, row in enumerate(values):
if i != 0:
sql_query.append(", ")
SQLQuery.join([SQLParam(row[k]) for k in keys], sep=", ", target=sql_query, prefix="(", suffix=")")
if _test: return sql_query
db_cursor = self._db_cursor()
if seqname is not False:
sql_query = self._process_insert_query(sql_query, tablename, seqname)
if isinstance(sql_query, tuple):
# for some databases, a separate query has to be made to find
# the id of the inserted row.
q1, q2 = sql_query
self._db_execute(db_cursor, q1)
self._db_execute(db_cursor, q2)
else:
self._db_execute(db_cursor, sql_query)
try:
out = db_cursor.fetchone()[0]
out = range(out-len(values)+1, out+1)
except Exception:
out = None
if not self.ctx.transactions:
self.ctx.commit()
return out
def update(self, tables, where, vars=None, _test=False, **values):
"""
Update `tables` with clause `where` (interpolated using `vars`)
and setting `values`.
>>> db = DB(None, {})
>>> name = 'Joseph'
>>> q = db.update('foo', where='name = $name', name='bob', age=2,
... created=SQLLiteral('NOW()'), vars=locals(), _test=True)
>>> q
<sql: "UPDATE foo SET age = 2, name = 'bob', created = NOW() WHERE name = 'Joseph'">
>>> q.query()
'UPDATE foo SET age = %s, name = %s, created = NOW() WHERE name = %s'
>>> q.values()
[2, 'bob', 'Joseph']
"""
if vars is None: vars = {}
where = self._where(where, vars)
query = (
"UPDATE " + sqllist(tables) +
" SET " + sqlwhere(values, ', ') +
" WHERE " + where)
if _test: return query
db_cursor = self._db_cursor()
self._db_execute(db_cursor, query)
if not self.ctx.transactions:
self.ctx.commit()
return db_cursor.rowcount
def delete(self, table, where, using=None, vars=None, _test=False):
"""
Deletes from `table` with clauses `where` and `using`.
>>> db = DB(None, {})
>>> name = 'Joe'
>>> db.delete('foo', where='name = $name', vars=locals(), _test=True)
<sql: "DELETE FROM foo WHERE name = 'Joe'">
"""
if vars is None: vars = {}
where = self._where(where, vars)
q = 'DELETE FROM ' + table
if using: q += ' USING ' + sqllist(using)
if where: q += ' WHERE ' + where
if _test: return q
db_cursor = self._db_cursor()
self._db_execute(db_cursor, q)
if not self.ctx.transactions:
self.ctx.commit()
return db_cursor.rowcount
def _process_insert_query(self, query, tablename, seqname):
return query
def transaction(self):
"""Start a transaction."""
return Transaction(self.ctx)
class PostgresDB(DB):
"""Postgres driver."""
def __init__(self, **keywords):
if 'pw' in keywords:
keywords['password'] = keywords.pop('pw')
db_module = import_driver(["psycopg2", "psycopg", "pgdb"], preferred=keywords.pop('driver', None))
if db_module.__name__ == "psycopg2":
import psycopg2.extensions
psycopg2.extensions.register_type(psycopg2.extensions.UNICODE)
if db_module.__name__ == "pgdb" and 'port' in keywords:
keywords["host"] += ":" + str(keywords.pop('port'))
# if db is not provided postgres driver will take it from PGDATABASE environment variable
if 'db' in keywords:
keywords['database'] = keywords.pop('db')
self.dbname = "postgres"
self.paramstyle = db_module.paramstyle
DB.__init__(self, db_module, keywords)
self.supports_multiple_insert = True
self._sequences = None
def _process_insert_query(self, query, tablename, seqname):
if seqname is None:
# when seqname is not provided guess the seqname and make sure it exists
seqname = tablename + "_id_seq"
if seqname not in self._get_all_sequences():
seqname = None
if seqname:
query += "; SELECT currval('%s')" % seqname
return query
def _get_all_sequences(self):
"""Query postgres to find names of all sequences used in this database."""
if self._sequences is None:
q = "SELECT c.relname FROM pg_class c WHERE c.relkind = 'S'"
self._sequences = set([c.relname for c in self.query(q)])
return self._sequences
def _connect(self, keywords):
conn = DB._connect(self, keywords)
try:
conn.set_client_encoding('UTF8')
except AttributeError:
# fallback for pgdb driver
conn.cursor().execute("set client_encoding to 'UTF-8'")
return conn
def _connect_with_pooling(self, keywords):
conn = DB._connect_with_pooling(self, keywords)
conn._con._con.set_client_encoding('UTF8')
return conn
class MySQLDB(DB):
def __init__(self, **keywords):
import MySQLdb as db
if 'pw' in keywords:
keywords['passwd'] = keywords['pw']
del keywords['pw']
if 'charset' not in keywords:
keywords['charset'] = 'utf8'
elif keywords['charset'] is None:
del keywords['charset']
self.paramstyle = db.paramstyle = 'pyformat' # it's both, like psycopg
self.dbname = "mysql"
DB.__init__(self, db, keywords)
self.supports_multiple_insert = True
def _process_insert_query(self, query, tablename, seqname):
return query, SQLQuery('SELECT last_insert_id();')
def _get_insert_default_values_query(self, table):
return "INSERT INTO %s () VALUES()" % table
def import_driver(drivers, preferred=None):
"""Import the first available driver or preferred driver.
"""
if preferred:
drivers = [preferred]
for d in drivers:
try:
return __import__(d, None, None, ['x'])
except ImportError:
pass
raise ImportError("Unable to import " + " or ".join(drivers))
class SqliteDB(DB):
def __init__(self, **keywords):
db = import_driver(["sqlite3", "pysqlite2.dbapi2", "sqlite"], preferred=keywords.pop('driver', None))
if db.__name__ in ["sqlite3", "pysqlite2.dbapi2"]:
db.paramstyle = 'qmark'
# sqlite driver doesn't create datatime objects for timestamp columns unless `detect_types` option is passed.
# It seems to be supported in sqlite3 and pysqlite2 drivers, not surte about sqlite.
keywords.setdefault('detect_types', db.PARSE_DECLTYPES)
self.paramstyle = db.paramstyle
keywords['database'] = keywords.pop('db')
keywords['pooling'] = False # sqlite don't allows connections to be shared by threads
self.dbname = "sqlite"
DB.__init__(self, db, keywords)
def _process_insert_query(self, query, tablename, seqname):
return query, SQLQuery('SELECT last_insert_rowid();')
def query(self, *a, **kw):
out = DB.query(self, *a, **kw)
if isinstance(out, iterbetter):
del out.__len__
return out
class FirebirdDB(DB):
"""Firebird Database.
"""
def __init__(self, **keywords):
try:
import kinterbasdb as db
except Exception:
db = None
pass
if 'pw' in keywords:
keywords['passwd'] = keywords['pw']
del keywords['pw']
keywords['database'] = keywords['db']
del keywords['db']
self.paramstyle = db.paramstyle
DB.__init__(self, db, keywords)
def delete(self, table, where=None, using=None, vars=None, _test=False):
# firebird doesn't support using clause
using=None
return DB.delete(self, table, where, using, vars, _test)
def sql_clauses(self, what, tables, where, group, order, limit, offset):
return (
('SELECT', ''),
('FIRST', limit),
('SKIP', offset),
('', what),
('FROM', sqllist(tables)),
('WHERE', where),
('GROUP BY', group),
('ORDER BY', order)
)
class MSSQLDB(DB):
def __init__(self, **keywords):
import pymssql as db
if 'pw' in keywords:
keywords['password'] = keywords.pop('pw')
keywords['database'] = keywords.pop('db')
self.dbname = "mssql"
DB.__init__(self, db, keywords)
def _process_query(self, sql_query):
"""Takes the SQLQuery object and returns query string and parameters.
"""
# MSSQLDB expects params to be a tuple.
# Overwriting the default implementation to convert params to tuple.
paramstyle = getattr(self, 'paramstyle', 'pyformat')
query = sql_query.query(paramstyle)
params = sql_query.values()
return query, tuple(params)
def sql_clauses(self, what, tables, where, group, order, limit, offset):
return (
('SELECT', what),
('TOP', limit),
('FROM', sqllist(tables)),
('WHERE', where),
('GROUP BY', group),
('ORDER BY', order),
('OFFSET', offset))
def _test(self):
"""Test LIMIT.
Fake presence of pymssql module for running tests.
>>> import sys
>>> sys.modules['pymssql'] = sys.modules['sys']
MSSQL has TOP clause instead of LIMIT clause.
>>> db = MSSQLDB(db='test', user='joe', pw='secret')
>>> db.select('foo', limit=4, _test=True)
<sql: 'SELECT * TOP 4 FROM foo'>
"""
pass
class OracleDB(DB):
def __init__(self, **keywords):
import cx_Oracle as db
if 'pw' in keywords:
keywords['password'] = keywords.pop('pw')
#@@ TODO: use db.makedsn if host, port is specified
keywords['dsn'] = keywords.pop('db')
self.dbname = 'oracle'
db.paramstyle = 'numeric'
self.paramstyle = db.paramstyle
# oracle doesn't support pooling
keywords.pop('pooling', None)
DB.__init__(self, db, keywords)
def _process_insert_query(self, query, tablename, seqname):
if seqname is None:
# It is not possible to get seq name from table name in Oracle
return query
else:
return query + "; SELECT %s.currval FROM dual" % seqname
def dburl2dict(url):
"""
Takes a URL to a database and parses it into an equivalent dictionary.
>>> dburl2dict('postgres://james:day@serverfarm.example.net:5432/mygreatdb')
{'host': 'serverfarm.example.net', 'pw': 'day', 'dbn': 'postgres', 'db': 'mygreatdb', 'port': '5432', 'user': 'james'}
"""
dbn, rest = url.split('://', 1)
user, rest = rest.split(':', 1)
pw, rest = rest.split('@', 1)
host, rest = rest.split(':', 1)
port, rest = rest.split('/', 1)
db = rest
return dict(dbn=dbn, user=user, pw=pw, host=host, port=port, db=db)
_databases = {}
def database(dburl=None, **params):
"""Creates appropriate database using params.
Pooling will be enabled if DBUtils module is available.
Pooling can be disabled by passing pooling=False in params.
"""
if not dburl and not params:
dburl = os.environ['DATABASE_URL']
if dburl:
params = dburl2dict(dburl)
dbn = params.pop('dbn')
if dbn in _databases:
return _databases[dbn](**params)
else:
raise UnknownDB, dbn
def register_database(name, clazz):
"""
Register a database.
>>> class LegacyDB(DB):
... def __init__(self, **params):
... pass
...
>>> register_database('legacy', LegacyDB)
>>> db = database(dbn='legacy', db='test', user='joe', passwd='secret')
"""
_databases[name] = clazz
register_database('mysql', MySQLDB)
register_database('postgres', PostgresDB)
register_database('sqlite', SqliteDB)
register_database('firebird', FirebirdDB)
register_database('mssql', MSSQLDB)
register_database('oracle', OracleDB)
def _interpolate(format):
"""
Takes a format string and returns a list of 2-tuples of the form
(boolean, string) where boolean says whether string should be evaled
or not.
from <http://lfw.org/python/Itpl.py> (public domain, Ka-Ping Yee)
"""
from tokenize import tokenprog
def matchorfail(text, pos):
match = tokenprog.match(text, pos)
if match is None:
raise _ItplError(text, pos)
return match, match.end()
namechars = "abcdefghijklmnopqrstuvwxyz" \
"ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789_";
chunks = []
pos = 0
while 1:
dollar = format.find("$", pos)
if dollar < 0:
break
nextchar = format[dollar + 1]
if nextchar == "{":
chunks.append((0, format[pos:dollar]))
pos, level = dollar + 2, 1
while level:
match, pos = matchorfail(format, pos)
tstart, tend = match.regs[3]
token = format[tstart:tend]
if token == "{":
level = level + 1
elif token == "}":
level = level - 1
chunks.append((1, format[dollar + 2:pos - 1]))
elif nextchar in namechars:
chunks.append((0, format[pos:dollar]))
match, pos = matchorfail(format, dollar + 1)
while pos < len(format):
if format[pos] == "." and \
pos + 1 < len(format) and format[pos + 1] in namechars:
match, pos = matchorfail(format, pos + 1)
elif format[pos] in "([":
pos, level = pos + 1, 1
while level:
match, pos = matchorfail(format, pos)
tstart, tend = match.regs[3]
token = format[tstart:tend]
if token[0] in "([":
level = level + 1
elif token[0] in ")]":
level = level - 1
else:
break
chunks.append((1, format[dollar + 1:pos]))
else:
chunks.append((0, format[pos:dollar + 1]))
pos = dollar + 1 + (nextchar == "$")
if pos < len(format):
chunks.append((0, format[pos:]))
return chunks
if __name__ == "__main__":
import doctest
doctest.testmod()
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