109 lines
4.8 KiB
Python
109 lines
4.8 KiB
Python
from __future__ import unicode_literals
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from django.db.backends import BaseDatabaseIntrospection, FieldInfo
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class DatabaseIntrospection(BaseDatabaseIntrospection):
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# Maps type codes to Django Field types.
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data_types_reverse = {
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16: 'BooleanField',
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17: 'BinaryField',
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20: 'BigIntegerField',
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21: 'SmallIntegerField',
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23: 'IntegerField',
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25: 'TextField',
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700: 'FloatField',
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701: 'FloatField',
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869: 'GenericIPAddressField',
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1042: 'CharField', # blank-padded
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1043: 'CharField',
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1082: 'DateField',
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1083: 'TimeField',
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1114: 'DateTimeField',
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1184: 'DateTimeField',
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1266: 'TimeField',
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1700: 'DecimalField',
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}
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def get_table_list(self, cursor):
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"Returns a list of table names in the current database."
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cursor.execute("""
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SELECT c.relname
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FROM pg_catalog.pg_class c
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LEFT JOIN pg_catalog.pg_namespace n ON n.oid = c.relnamespace
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WHERE c.relkind IN ('r', 'v', '')
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AND n.nspname NOT IN ('pg_catalog', 'pg_toast')
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AND pg_catalog.pg_table_is_visible(c.oid)""")
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return [row[0] for row in cursor.fetchall()]
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def get_table_description(self, cursor, table_name):
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"Returns a description of the table, with the DB-API cursor.description interface."
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# As cursor.description does not return reliably the nullable property,
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# we have to query the information_schema (#7783)
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cursor.execute("""
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SELECT column_name, is_nullable
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FROM information_schema.columns
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WHERE table_name = %s""", [table_name])
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null_map = dict(cursor.fetchall())
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cursor.execute("SELECT * FROM %s LIMIT 1" % self.connection.ops.quote_name(table_name))
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return [FieldInfo(*(line[:6] + (null_map[line[0]]=='YES',)))
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for line in cursor.description]
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def get_relations(self, cursor, table_name):
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"""
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Returns a dictionary of {field_index: (field_index_other_table, other_table)}
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representing all relationships to the given table. Indexes are 0-based.
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"""
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cursor.execute("""
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SELECT con.conkey, con.confkey, c2.relname
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FROM pg_constraint con, pg_class c1, pg_class c2
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WHERE c1.oid = con.conrelid
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AND c2.oid = con.confrelid
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AND c1.relname = %s
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AND con.contype = 'f'""", [table_name])
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relations = {}
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for row in cursor.fetchall():
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# row[0] and row[1] are single-item lists, so grab the single item.
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relations[row[0][0] - 1] = (row[1][0] - 1, row[2])
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return relations
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def get_key_columns(self, cursor, table_name):
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key_columns = []
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cursor.execute("""
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SELECT kcu.column_name, ccu.table_name AS referenced_table, ccu.column_name AS referenced_column
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FROM information_schema.constraint_column_usage ccu
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LEFT JOIN information_schema.key_column_usage kcu
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ON ccu.constraint_catalog = kcu.constraint_catalog
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AND ccu.constraint_schema = kcu.constraint_schema
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AND ccu.constraint_name = kcu.constraint_name
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LEFT JOIN information_schema.table_constraints tc
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ON ccu.constraint_catalog = tc.constraint_catalog
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AND ccu.constraint_schema = tc.constraint_schema
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AND ccu.constraint_name = tc.constraint_name
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WHERE kcu.table_name = %s AND tc.constraint_type = 'FOREIGN KEY'""" , [table_name])
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key_columns.extend(cursor.fetchall())
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return key_columns
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def get_indexes(self, cursor, table_name):
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# This query retrieves each index on the given table, including the
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# first associated field name
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cursor.execute("""
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SELECT attr.attname, idx.indkey, idx.indisunique, idx.indisprimary
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FROM pg_catalog.pg_class c, pg_catalog.pg_class c2,
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pg_catalog.pg_index idx, pg_catalog.pg_attribute attr
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WHERE c.oid = idx.indrelid
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AND idx.indexrelid = c2.oid
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AND attr.attrelid = c.oid
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AND attr.attnum = idx.indkey[0]
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AND c.relname = %s""", [table_name])
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indexes = {}
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for row in cursor.fetchall():
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# row[1] (idx.indkey) is stored in the DB as an array. It comes out as
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# a string of space-separated integers. This designates the field
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# indexes (1-based) of the fields that have indexes on the table.
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# Here, we skip any indexes across multiple fields.
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if ' ' in row[1]:
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continue
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indexes[row[0]] = {'primary_key': row[3], 'unique': row[2]}
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return indexes
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