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from __future__ import unicode_literals
from collections import namedtuple
from django.db.backends.base.introspection import (
BaseDatabaseIntrospection, FieldInfo, TableInfo,
)
from django.utils.encoding import force_text
FieldInfo = namedtuple('FieldInfo', FieldInfo._fields + ('default',))
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',
1266: 'TimeField',
1700: 'DecimalField',
2950: 'UUIDField',
}
ignored_tables = []
_get_indexes_query = """
SELECT attr.attname, idx.indkey, idx.indisunique, idx.indisprimary
FROM pg_catalog.pg_class c, pg_catalog.pg_class c2,
pg_catalog.pg_index idx, pg_catalog.pg_attribute attr
WHERE c.oid = idx.indrelid
AND idx.indexrelid = c2.oid
AND attr.attrelid = c.oid
AND attr.attnum = idx.indkey[0]
AND c.relname = %s"""
def get_field_type(self, data_type, description):
field_type = super(DatabaseIntrospection, self).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):
"""
Returns a list of table and view names in the current database.
"""
cursor.execute("""
SELECT c.relname, c.relkind
FROM pg_catalog.pg_class c
LEFT JOIN pg_catalog.pg_namespace n ON n.oid = c.relnamespace
WHERE c.relkind IN ('r', 'v')
AND n.nspname NOT IN ('pg_catalog', 'pg_toast')
AND pg_catalog.pg_table_is_visible(c.oid)""")
return [TableInfo(row[0], {'r': 't', 'v': 'v'}.get(row[1]))
for row in cursor.fetchall()
if row[0] not in self.ignored_tables]
def get_table_description(self, cursor, table_name):
"Returns a description of the table, with the DB-API cursor.description interface."
# As cursor.description does not return reliably the nullable property,
# we have to query the information_schema (#7783)
cursor.execute("""
SELECT column_name, is_nullable, column_default
FROM information_schema.columns
WHERE table_name = %s""", [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(*(
(force_text(line[0]),) +
line[1:6] +
(field_map[force_text(line[0])][0] == 'YES', field_map[force_text(line[0])][1])
)) for line in cursor.description
]
def get_relations(self, cursor, table_name):
"""
Returns 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])
relations = {}
for row in cursor.fetchall():
relations[row[1]] = (row[2], row[0])
return relations
def get_key_columns(self, cursor, table_name):
key_columns = []
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])
key_columns.extend(cursor.fetchall())
return key_columns
def get_indexes(self, cursor, table_name):
# This query retrieves each index on the given table, including the
# first associated field name
cursor.execute(self._get_indexes_query, [table_name])
indexes = {}
for row in cursor.fetchall():
# row[1] (idx.indkey) is stored in the DB as an array. It comes out as
# a string of space-separated integers. This designates the field
# indexes (1-based) of the fields that have indexes on the table.
# Here, we skip any indexes across multiple fields.
if ' ' in row[1]:
continue
if row[0] not in indexes:
indexes[row[0]] = {'primary_key': False, 'unique': False}
# It's possible to have the unique and PK constraints in separate indexes.
if row[3]:
indexes[row[0]]['primary_key'] = True
if row[2]:
indexes[row[0]]['unique'] = True
return indexes
def get_constraints(self, cursor, table_name):
"""
Retrieves any constraints or keys (unique, pk, fk, check, index) across one or more columns.
"""
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.
# The subquery containing generate_series can be replaced with
# "WITH ORDINALITY" when support for PostgreSQL 9.3 is dropped.
cursor.execute("""
SELECT
c.conname,
array(
SELECT attname
FROM (
SELECT unnest(c.conkey) AS colid,
generate_series(1, array_length(c.conkey, 1)) AS arridx
) AS cols
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])
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 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,
}
# Now get indexes
cursor.execute("""
SELECT
indexname, array_agg(attname), indisunique, indisprimary,
array_agg(ordering), amname
FROM (
SELECT
c2.relname as indexname, idx.*, attr.attname, am.amname,
CASE
WHEN am.amcanorder THEN
CASE (option & 1)
WHEN 1 THEN 'DESC' ELSE 'ASC'
END
END as ordering
FROM (
SELECT
*, unnest(i.indkey) as key, unnest(i.indoption) as option
FROM pg_index i
) idx, pg_class c, pg_class c2, pg_am am, pg_attribute attr
WHERE c.oid=idx.indrelid
AND idx.indexrelid=c2.oid
AND attr.attrelid=c.oid
AND attr.attnum=idx.key
AND c2.relam=am.oid
AND c.relname = %s
) s2
GROUP BY indexname, indisunique, indisprimary, amname;
""", [table_name])
for index, columns, unique, primary, orders, type_ in cursor.fetchall():
if index not in constraints:
constraints[index] = {
"columns": columns,
"orders": orders,
"primary_key": primary,
"unique": unique,
"foreign_key": None,
"check": False,
"index": True,
"type": type_,
}
return constraints
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