Fixed #25476 -- Allowed PostgreSQL introspection to work regardless of table owner.

django/db/backends/postgresql/introspection.py

@@ -149,65 +149,43 @@ class DatabaseIntrospection(BaseDatabaseIntrospection):
         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
-        # This will get PKs, FKs, and uniques, but not CHECK
+        # 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
-                kc.constraint_name,
-                kc.column_name,
-                c.constraint_type,
-                array(SELECT table_name::text || '.' || column_name::text
-                      FROM information_schema.constraint_column_usage
-                      WHERE constraint_name = kc.constraint_name)
-            FROM information_schema.key_column_usage AS kc
-            JOIN information_schema.table_constraints AS c ON
-                kc.table_schema = c.table_schema AND
-                kc.table_name = c.table_name AND
-                kc.constraint_name = c.constraint_name
-            WHERE
-                kc.table_schema = %s AND
-                kc.table_name = %s
-            ORDER BY kc.ordinal_position ASC
+                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, column, kind, used_cols in cursor.fetchall():
-            # If we're the first column, make the record
-            if constraint not in constraints:
-                constraints[constraint] = {
-                    "columns": [],
-                    "primary_key": kind.lower() == "primary key",
-                    "unique": kind.lower() in ["primary key", "unique"],
-                    "foreign_key": tuple(used_cols[0].split(".", 1)) if kind.lower() == "foreign key" else None,
-                    "check": False,
-                    "index": False,
-                }
-            # Record the details
-            constraints[constraint]['columns'].append(column)
-        # Now get CHECK constraint columns
-        cursor.execute("""
-            SELECT kc.constraint_name, kc.column_name
-            FROM information_schema.constraint_column_usage AS kc
-            JOIN information_schema.table_constraints AS c ON
-                kc.table_schema = c.table_schema AND
-                kc.table_name = c.table_name AND
-                kc.constraint_name = c.constraint_name
-            WHERE
-                c.constraint_type = 'CHECK' AND
-                kc.table_schema = %s AND
-                kc.table_name = %s
-        """, ["public", table_name])
-        for constraint, column in cursor.fetchall():
-            # If we're the first column, make the record
-            if constraint not in constraints:
-                constraints[constraint] = {
-                    "columns": [],
-                    "primary_key": False,
-                    "unique": False,
-                    "foreign_key": None,
-                    "check": True,
-                    "index": False,
-                }
-            # Record the details
-            constraints[constraint]['columns'].append(column)
+        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