244 lines
10 KiB
Python
244 lines
10 KiB
Python
import warnings
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from django.db.backends.base.introspection import (
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BaseDatabaseIntrospection, FieldInfo, TableInfo,
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)
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from django.db.models.indexes import Index
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from django.utils.deprecation import RemovedInDjango21Warning
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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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2950: 'UUIDField',
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}
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ignored_tables = []
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_get_indexes_query = """
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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"""
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def get_field_type(self, data_type, description):
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field_type = super().get_field_type(data_type, description)
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if description.default and 'nextval' in description.default:
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if field_type == 'IntegerField':
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return 'AutoField'
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elif field_type == 'BigIntegerField':
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return 'BigAutoField'
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return field_type
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def get_table_list(self, cursor):
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"""Return a list of table and view names in the current database."""
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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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"""
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Return a description of the table with the DB-API cursor.description
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interface.
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"""
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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 = {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 [
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FieldInfo(*(line[0:6] + (field_map[line.name][0] == 'YES', field_map[line.name][1])))
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for line in cursor.description
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]
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def get_relations(self, cursor, table_name):
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"""
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Return a dictionary of {field_name: (field_name_other_table, other_table)}
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representing all relationships to the given table.
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"""
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cursor.execute("""
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SELECT c2.relname, a1.attname, a2.attname
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FROM pg_constraint con
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LEFT JOIN pg_class c1 ON con.conrelid = c1.oid
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LEFT JOIN pg_class c2 ON con.confrelid = c2.oid
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LEFT JOIN pg_attribute a1 ON c1.oid = a1.attrelid AND a1.attnum = con.conkey[1]
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LEFT JOIN pg_attribute a2 ON c2.oid = a2.attrelid AND a2.attnum = con.confkey[1]
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WHERE 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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relations[row[1]] = (row[2], row[0])
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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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warnings.warn(
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"get_indexes() is deprecated in favor of get_constraints().",
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RemovedInDjango21Warning, stacklevel=2
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)
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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(self._get_indexes_query, [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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Retrieve any constraints or keys (unique, pk, fk, check, index) across
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one or more columns. Also retrieve the definition of expression-based
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indexes.
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"""
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constraints = {}
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# Loop over the key table, collecting things as constraints. The column
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# array must return column names in the same order in which they were
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# created.
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# The subquery containing generate_series can be replaced with
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# "WITH ORDINALITY" when support for PostgreSQL 9.3 is dropped.
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cursor.execute("""
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SELECT
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c.conname,
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array(
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SELECT attname
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FROM (
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SELECT unnest(c.conkey) AS colid,
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generate_series(1, array_length(c.conkey, 1)) AS arridx
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) AS cols
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JOIN pg_attribute AS ca ON cols.colid = ca.attnum
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WHERE ca.attrelid = c.conrelid
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ORDER BY cols.arridx
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),
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c.contype,
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(SELECT fkc.relname || '.' || fka.attname
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FROM pg_attribute AS fka
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JOIN pg_class AS fkc ON fka.attrelid = fkc.oid
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WHERE fka.attrelid = c.confrelid AND fka.attnum = c.confkey[1]),
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cl.reloptions
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FROM pg_constraint AS c
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JOIN pg_class AS cl ON c.conrelid = cl.oid
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JOIN pg_namespace AS ns ON cl.relnamespace = ns.oid
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WHERE ns.nspname = %s AND cl.relname = %s
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""", ["public", table_name])
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for constraint, columns, kind, used_cols, options in cursor.fetchall():
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constraints[constraint] = {
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"columns": columns,
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"primary_key": kind == "p",
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"unique": kind in ["p", "u"],
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"foreign_key": tuple(used_cols.split(".", 1)) if kind == "f" else None,
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"check": kind == "c",
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"index": False,
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"definition": None,
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"options": options,
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}
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# Now get indexes
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# The row_number() function for ordering the index fields can be
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# replaced by WITH ORDINALITY in the unnest() functions when support
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# for PostgreSQL 9.3 is dropped.
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cursor.execute("""
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SELECT
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indexname, array_agg(attname ORDER BY rnum), indisunique, indisprimary,
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array_agg(ordering ORDER BY rnum), amname, exprdef, s2.attoptions
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FROM (
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SELECT
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row_number() OVER () as rnum, c2.relname as indexname,
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idx.*, attr.attname, am.amname,
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CASE
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WHEN idx.indexprs IS NOT NULL THEN
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pg_get_indexdef(idx.indexrelid)
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END AS exprdef,
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CASE am.amname
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WHEN 'btree' THEN
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CASE (option & 1)
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WHEN 1 THEN 'DESC' ELSE 'ASC'
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END
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END as ordering,
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c2.reloptions as attoptions
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FROM (
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SELECT
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*, unnest(i.indkey) as key, unnest(i.indoption) as option
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FROM pg_index i
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) idx
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LEFT JOIN pg_class c ON idx.indrelid = c.oid
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LEFT JOIN pg_class c2 ON idx.indexrelid = c2.oid
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LEFT JOIN pg_am am ON c2.relam = am.oid
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LEFT JOIN pg_attribute attr ON attr.attrelid = c.oid AND attr.attnum = idx.key
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WHERE c.relname = %s
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) s2
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GROUP BY indexname, indisunique, indisprimary, amname, exprdef, attoptions;
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""", [table_name])
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for index, columns, unique, primary, orders, type_, definition, options in cursor.fetchall():
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if index not in constraints:
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constraints[index] = {
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"columns": columns if columns != [None] else [],
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"orders": orders if orders != [None] else [],
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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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"type": Index.suffix if type_ == 'btree' else type_,
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"definition": definition,
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"options": options,
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}
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return constraints
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