225 lines
9.7 KiB
Python
225 lines
9.7 KiB
Python
from __future__ import unicode_literals
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from collections import namedtuple
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from django.db.backends import BaseDatabaseIntrospection, FieldInfo, TableInfo
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from django.utils.encoding import force_text
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FieldInfo = namedtuple('FieldInfo', FieldInfo._fields + ('default',))
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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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ignored_tables = []
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def get_field_type(self, data_type, description):
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field_type = super(DatabaseIntrospection, self).get_field_type(data_type, description)
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if field_type == 'IntegerField' and description.default and 'nextval' in description.default:
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return 'AutoField'
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return field_type
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def get_table_list(self, cursor):
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"""
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Returns a list of table and view names in the current database.
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"""
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cursor.execute("""
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SELECT c.relname, c.relkind
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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 [TableInfo(row[0], {'r': 't', 'v': 'v'}.get(row[1]))
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for row in cursor.fetchall()
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if row[0] not in self.ignored_tables]
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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, column_default
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FROM information_schema.columns
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WHERE table_name = %s""", [table_name])
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field_map = dict((line[0], line[1:]) for line in 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(*((force_text(line[0]),) + line[1:6]
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+ (field_map[force_text(line[0])][0] == 'YES', field_map[force_text(line[0])][1])))
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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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if row[0] not in indexes:
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indexes[row[0]] = {'primary_key': False, 'unique': False}
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# It's possible to have the unique and PK constraints in separate indexes.
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if row[3]:
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indexes[row[0]]['primary_key'] = True
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if row[2]:
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indexes[row[0]]['unique'] = True
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return indexes
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def get_constraints(self, cursor, table_name):
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"""
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Retrieves any constraints or keys (unique, pk, fk, check, index) across one or more columns.
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"""
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constraints = {}
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# Loop over the key table, collecting things as constraints
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# This will get PKs, FKs, and uniques, but not CHECK
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cursor.execute("""
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SELECT
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kc.constraint_name,
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kc.column_name,
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c.constraint_type,
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array(SELECT table_name::text || '.' || column_name::text
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FROM information_schema.constraint_column_usage
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WHERE constraint_name = kc.constraint_name)
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FROM information_schema.key_column_usage AS kc
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JOIN information_schema.table_constraints AS c ON
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kc.table_schema = c.table_schema AND
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kc.table_name = c.table_name AND
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kc.constraint_name = c.constraint_name
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WHERE
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kc.table_schema = %s AND
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kc.table_name = %s
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ORDER BY kc.ordinal_position ASC
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""", ["public", table_name])
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for constraint, column, kind, used_cols in cursor.fetchall():
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# If we're the first column, make the record
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if constraint not in constraints:
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constraints[constraint] = {
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"columns": [],
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"primary_key": kind.lower() == "primary key",
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"unique": kind.lower() in ["primary key", "unique"],
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"foreign_key": tuple(used_cols[0].split(".", 1)) if kind.lower() == "foreign key" else None,
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"check": False,
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"index": False,
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}
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# Record the details
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constraints[constraint]['columns'].append(column)
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# Now get CHECK constraint columns
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cursor.execute("""
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SELECT kc.constraint_name, kc.column_name
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FROM information_schema.constraint_column_usage AS kc
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JOIN information_schema.table_constraints AS c ON
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kc.table_schema = c.table_schema AND
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kc.table_name = c.table_name AND
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kc.constraint_name = c.constraint_name
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WHERE
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c.constraint_type = 'CHECK' AND
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kc.table_schema = %s AND
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kc.table_name = %s
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""", ["public", table_name])
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for constraint, column in cursor.fetchall():
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# If we're the first column, make the record
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if constraint not in constraints:
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constraints[constraint] = {
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"columns": [],
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"primary_key": False,
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"unique": False,
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"foreign_key": None,
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"check": True,
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"index": False,
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}
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# Record the details
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constraints[constraint]['columns'].append(column)
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# Now get indexes
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cursor.execute("""
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SELECT
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c2.relname,
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ARRAY(
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SELECT (SELECT attname FROM pg_catalog.pg_attribute WHERE attnum = i AND attrelid = c.oid)
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FROM unnest(idx.indkey) i
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),
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idx.indisunique,
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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
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WHERE c.oid = idx.indrelid
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AND idx.indexrelid = c2.oid
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AND c.relname = %s
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""", [table_name])
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for index, columns, unique, primary in cursor.fetchall():
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if index not in constraints:
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constraints[index] = {
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"columns": list(columns),
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"primary_key": primary,
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"unique": unique,
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"foreign_key": None,
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"check": False,
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"index": True,
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}
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return constraints
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