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index.py
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index.py
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from schemaobject.collections import OrderedDict
def IndexSchemaBuilder(table):
"""
Returns a dictionary loaded with all of the indexes available in the table.
``table`` must be an instance of TableSchema.
.. note::
This function is automatically called for you and set to
``schema.databases[name].tables[name].indexes`` when you create an instance of SchemaObject
"""
conn = table.parent.parent.connection
idx = OrderedDict()
indexes = conn.execute("SHOW INDEXES FROM `%s`.`%s`" % (table.parent.name, table.name))
if not indexes:
return idx
for index in indexes:
n = index['Key_name']
if n not in idx:
Indexitem = IndexSchema(name=n, parent=table)
Indexitem.non_unique = (bool(index['Non_unique'])) # == not unique
Indexitem.table_name = index['Table']
key_type = index['Index_type'].upper()
if index['Key_name'].upper() == "PRIMARY":
Indexitem.kind = "PRIMARY"
elif not Indexitem.non_unique:
Indexitem.kind = "UNIQUE"
elif key_type in ('FULLTEXT', 'SPATIAL'):
Indexitem.kind = key_type
else:
Indexitem.kind = "INDEX"
if key_type in ('BTREE', 'HASH', 'RTREE'):
Indexitem.type = key_type
Indexitem.collation = index['Collation']
Indexitem.comment = index['Comment']
idx[n] = Indexitem
if index['Column_name'] not in idx[n].fields:
idx[n].fields.insert(index['Seq_in_index'], (index['Column_name'], index['Sub_part'] or 0))
return idx
class IndexSchema(object):
"""
Object representation of a single index.
Supports equality and inequality comparison of IndexSchema.
``name`` is the column name.
``parent`` is an instance of TableSchema
.. note::
IndexSchema objects are automatically created for you by IndexSchemaBuilder
and loaded under ``schema.databases[name].tables[name].indexes``
Example
>>> schema.databases['sakila'].tables['rental'].indexes.keys()
['PRIMARY', 'rental_date', 'idx_fk_inventory_id', 'idx_fk_customer_id', 'idx_fk_staff_id']
Index Attributes
>>> schema.databases['sakila'].tables['rental'].indexes['idx_fk_customer_id'].name
'idx_fk_customer_id'
>>> schema.databases['sakila'].tables['rental'].indexes['idx_fk_customer_id'].table_name
'rental'
>>> schema.databases['sakila'].tables['rental'].indexes['idx_fk_customer_id'].non_unique
True
>>> schema.databases['sakila'].tables['rental'].indexes['idx_fk_customer_id'].fields
[('customer_id', None)]
#possible types: BTREE, RTREE, HASH
>>> schema.databases['sakila'].tables['rental'].indexes['idx_fk_customer_id'].type
'BTREE'
#possible kinds: PRIMARY, UNIQUE, FULLTEXT, SPATIAL, INDEX
>>> schema.databases['sakila'].tables['rental'].indexes['rental_date'].kind
'UNIQUE'
>>> schema.databases['sakila'].tables['film_text'].indexes['idx_title_description'].kind
'FULLTEXT'
#fields is a list of tuples (field_name, sub_part_length)
>>> schema.databases['sakila'].tables['film_text'].indexes['idx_title_description'].fields
[('title', 0), ('description', 0)]
#collation will always be A in MySQL 5.x - 6.x
>>> schema.databases['sakila'].tables['rental'].indexes['idx_fk_customer_id'].collation
'A'
>>> schema.databases['sakila'].tables['rental'].indexes['idx_fk_customer_id'].comment
''
"""
def __init__(self, name, parent):
self.parent = parent
self.name = name
self.table_name = None
self.non_unique = False
self.fields = []
self.type = None
self.kind = None
self.collation = None #ignored by the parser. mysql 5.0+ all == A (ASC)
self.comment = None
@classmethod
def format_sub_part(self, field, length):
"""
Generate the SQL to format the sub_part length of an indexed column name
>>> schemaobjects.index.IndexSchema.format_sub_part('column', 0)
'`column`'
>>> schemaobjects.index.IndexSchema.format_sub_part('column', 5)
'`column`(5)'
"""
try:
if not length:
raise ValueError
length = int(length)
return "`%s`(%d)" % (field, length)
except ValueError:
return "`%s`" % (field)
def create(self):
"""
Generate the SQL to create (ADD) this index
>>> schema.databases['sakila'].tables['film_text'].indexes['idx_title_description'].create()
'ADD FULLTEXT INDEX `idx_title_description` (`title`, `description`)'
>>> schema.databases['sakila'].tables['rental'].indexes['rental_date'].create()
'ADD UNIQUE INDEX `rental_date` (`rental_date`, `inventory_id`, `customer_id`) USING BTREE'
.. note:
Collation is ignored when creating an index (MySQL default is 'A').
"""
sql = []
if self.kind == "PRIMARY":
sql.append("ADD PRIMARY KEY")
elif self.kind == "UNIQUE":
sql.append("ADD UNIQUE INDEX `%s`" % self.name)
elif self.kind in ('FULLTEXT', 'SPATIAL'):
sql.append("ADD %s INDEX `%s`" % (self.kind, self.name))
else:
sql.append("ADD INDEX `%s`" % self.name)
sql.append("(%s)" % ", ".join([self.format_sub_part(f, l) for f, l in self.fields]))
if self.type in ('BTREE', 'HASH', 'RTREE'):
sql.append("USING %s" % self.type)
return ' '.join(sql)
def drop(self):
"""
Generate the SQL to drop this index
>>> schema.databases['sakila'].tables['rental'].indexes['PRIMARY'].drop()
'DROP PRIMARY KEY'
>>> schema.databases['sakila'].tables['rental'].indexes['rental_date'].drop()
'DROP INDEX `rental_date`'
"""
if self.name == 'PRIMARY':
return "DROP PRIMARY KEY"
else:
return "DROP INDEX `%s`" % (self.name)
def __eq__(self, other):
if not isinstance(other, IndexSchema):
return False
return ((self.name == other.name)
and (self.table_name == other.table_name)
and (self.type == other.type)
and (self.kind == other.kind)
and (self.collation == other.collation)
and (self.non_unique == other.non_unique)
and (self.fields == other.fields))
def __ne__(self, other):
return not self.__eq__(other)