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from django.db.backends.base.introspection import (
BaseDatabaseIntrospection, FieldInfo, TableInfo,
)
from django.db.models.indexes import Index
class DatabaseIntrospection(BaseDatabaseIntrospection):
# Maps type codes to Django Field types.
data_types_reverse = {
16: 'BooleanField',
17: 'BinaryField',
20: 'BigIntegerField',
21: 'SmallIntegerField',
23: 'IntegerField',
25: 'TextField',
700: 'FloatField',
701: 'FloatField',
869: 'GenericIPAddressField',
1042: 'CharField', # blank-padded
1043: 'CharField',
1082: 'DateField',
1083: 'TimeField',
1114: 'DateTimeField',
1184: 'DateTimeField',
1186: 'DurationField',
1266: 'TimeField',
1700: 'DecimalField',
2950: 'UUIDField',
}
ignored_tables = []
def get_field_type(self, data_type, description):
field_type = super().get_field_type(data_type, description)
if description.default and 'nextval' in description.default:
if field_type == 'IntegerField':
return 'AutoField'
elif field_type == 'BigIntegerField':
return 'BigAutoField'
return field_type
def get_table_list(self, cursor):
"""Return a list of table and view names in the current database."""
cursor.execute("""
SELECT c.relname,
CASE WHEN {} THEN 'p' WHEN c.relkind IN ('m', 'v') THEN 'v' ELSE 't' END
FROM pg_catalog.pg_class c
LEFT JOIN pg_catalog.pg_namespace n ON n.oid = c.relnamespace
WHERE c.relkind IN ('f', 'm', 'p', 'r', 'v')
AND n.nspname NOT IN ('pg_catalog', 'pg_toast')
AND pg_catalog.pg_table_is_visible(c.oid)
""".format('c.relispartition' if self.connection.features.supports_table_partitions else 'FALSE'))
return [TableInfo(*row) for row in cursor.fetchall() if row[0] not in self.ignored_tables]
def get_table_description(self, cursor, table_name):
"""
Return a description of the table with the DB-API cursor.description
interface.
"""
# Query the pg_catalog tables as cursor.description does not reliably
# return the nullable property and information_schema.columns does not
# contain details of materialized views.
cursor.execute("""
SELECT
a.attname AS column_name,
NOT (a.attnotnull OR (t.typtype = 'd' AND t.typnotnull)) AS is_nullable,
pg_get_expr(ad.adbin, ad.adrelid) AS column_default
FROM pg_attribute a
LEFT JOIN pg_attrdef ad ON a.attrelid = ad.adrelid AND a.attnum = ad.adnum
JOIN pg_type t ON a.atttypid = t.oid
JOIN pg_class c ON a.attrelid = c.oid
JOIN pg_namespace n ON c.relnamespace = n.oid
WHERE c.relkind IN ('f', 'm', 'p', 'r', 'v')
AND c.relname = %s
AND n.nspname NOT IN ('pg_catalog', 'pg_toast')
AND pg_catalog.pg_table_is_visible(c.oid)
""", [table_name])
field_map = {line[0]: line[1:] for line in cursor.fetchall()}
cursor.execute("SELECT * FROM %s LIMIT 1" % self.connection.ops.quote_name(table_name))
return [FieldInfo(*line[0:6], *field_map[line.name]) for line in cursor.description]
def get_sequences(self, cursor, table_name, table_fields=()):
cursor.execute("""
SELECT s.relname as sequence_name, col.attname
FROM pg_class s
JOIN pg_namespace sn ON sn.oid = s.relnamespace
JOIN pg_depend d ON d.refobjid = s.oid AND d.refclassid = 'pg_class'::regclass
JOIN pg_attrdef ad ON ad.oid = d.objid AND d.classid = 'pg_attrdef'::regclass
JOIN pg_attribute col ON col.attrelid = ad.adrelid AND col.attnum = ad.adnum
JOIN pg_class tbl ON tbl.oid = ad.adrelid
JOIN pg_namespace n ON n.oid = tbl.relnamespace
WHERE s.relkind = 'S'
AND d.deptype in ('a', 'n')
AND n.nspname = 'public'
AND tbl.relname = %s
""", [table_name])
return [
{'name': row[0], 'table': table_name, 'column': row[1]}
for row in cursor.fetchall()
]
def get_relations(self, cursor, table_name):
"""
Return a dictionary of {field_name: (field_name_other_table, other_table)}
representing all relationships to the given table.
"""
cursor.execute("""
SELECT c2.relname, a1.attname, a2.attname
FROM pg_constraint con
LEFT JOIN pg_class c1 ON con.conrelid = c1.oid
LEFT JOIN pg_class c2 ON con.confrelid = c2.oid
LEFT JOIN pg_attribute a1 ON c1.oid = a1.attrelid AND a1.attnum = con.conkey[1]
LEFT JOIN pg_attribute a2 ON c2.oid = a2.attrelid AND a2.attnum = con.confkey[1]
WHERE c1.relname = %s AND con.contype = 'f'
""", [table_name])
return {row[1]: (row[2], row[0]) for row in cursor.fetchall()}
def get_key_columns(self, cursor, table_name):
cursor.execute("""
SELECT kcu.column_name, ccu.table_name AS referenced_table, ccu.column_name AS referenced_column
FROM information_schema.constraint_column_usage ccu
LEFT JOIN information_schema.key_column_usage kcu
ON ccu.constraint_catalog = kcu.constraint_catalog
AND ccu.constraint_schema = kcu.constraint_schema
AND ccu.constraint_name = kcu.constraint_name
LEFT JOIN information_schema.table_constraints tc
ON ccu.constraint_catalog = tc.constraint_catalog
AND ccu.constraint_schema = tc.constraint_schema
AND ccu.constraint_name = tc.constraint_name
WHERE kcu.table_name = %s AND tc.constraint_type = 'FOREIGN KEY'
""", [table_name])
return cursor.fetchall()
def get_constraints(self, cursor, table_name):
"""
Retrieve any constraints or keys (unique, pk, fk, check, index) across
one or more columns. Also retrieve the definition of expression-based
indexes.
"""
constraints = {}
# Loop over the key table, collecting things as constraints. The column
# array must return column names in the same order in which they were
# created.
cursor.execute("""
SELECT
c.conname,
array(
SELECT attname
FROM unnest(c.conkey) WITH ORDINALITY cols(colid, arridx)
JOIN pg_attribute AS ca ON cols.colid = ca.attnum
WHERE ca.attrelid = c.conrelid
ORDER BY cols.arridx
),
c.contype,
(SELECT fkc.relname || '.' || fka.attname
FROM pg_attribute AS fka
JOIN pg_class AS fkc ON fka.attrelid = fkc.oid
WHERE fka.attrelid = c.confrelid AND fka.attnum = c.confkey[1]),
cl.reloptions
FROM pg_constraint AS c
JOIN pg_class AS cl ON c.conrelid = cl.oid
JOIN pg_namespace AS ns ON cl.relnamespace = ns.oid
WHERE ns.nspname = %s AND cl.relname = %s
""", ["public", table_name])
for constraint, columns, kind, used_cols, options in cursor.fetchall():
constraints[constraint] = {
"columns": columns,
"primary_key": kind == "p",
"unique": kind in ["p", "u"],
"foreign_key": tuple(used_cols.split(".", 1)) if kind == "f" else None,
"check": kind == "c",
"index": False,
"definition": None,
"options": options,
}
# Now get indexes
cursor.execute("""
SELECT
indexname, array_agg(attname ORDER BY arridx), indisunique, indisprimary,
array_agg(ordering ORDER BY arridx), amname, exprdef, s2.attoptions
FROM (
SELECT
c2.relname as indexname, idx.*, attr.attname, am.amname,
CASE
WHEN idx.indexprs IS NOT NULL THEN
pg_get_indexdef(idx.indexrelid)
END AS exprdef,
CASE am.amname
WHEN 'btree' THEN
CASE (option & 1)
WHEN 1 THEN 'DESC' ELSE 'ASC'
END
END as ordering,
c2.reloptions as attoptions
FROM (
SELECT *
FROM pg_index i, unnest(i.indkey, i.indoption) WITH ORDINALITY koi(key, option, arridx)
) idx
LEFT JOIN pg_class c ON idx.indrelid = c.oid
LEFT JOIN pg_class c2 ON idx.indexrelid = c2.oid
LEFT JOIN pg_am am ON c2.relam = am.oid
LEFT JOIN pg_attribute attr ON attr.attrelid = c.oid AND attr.attnum = idx.key
WHERE c.relname = %s
) s2
GROUP BY indexname, indisunique, indisprimary, amname, exprdef, attoptions;
""", [table_name])
for index, columns, unique, primary, orders, type_, definition, options in cursor.fetchall():
if index not in constraints:
basic_index = type_ == 'btree' and not index.endswith('_btree') and options is None
constraints[index] = {
"columns": columns if columns != [None] else [],
"orders": orders if orders != [None] else [],
"primary_key": primary,
"unique": unique,
"foreign_key": None,
"check": False,
"index": True,
"type": Index.suffix if basic_index else type_,
"definition": definition,
"options": options,
}
return constraints
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