information_schema.table_constraints.constraint_schema

mysql

type: VARCHAR NOT NULL
5.7-8

mariadb

type: NULL
Note:
Database name containing the constraint.
© 2022 MariaDB
5.1-10.8
type: VARCHAR NOT NULL
Note:
Database name containing the constraint.
© 2022 MariaDB
10.2-10.7

tidb

type: VARCHAR(64) NULL
Note:
The name of the database to which the constraint belongs.
© 2022 PingCAP
4-6.1

postgres

type: SQL_IDENTIFIER NULL
Note:
Name of the schema that contains the constraint
© 1996-2022 The PostgreSQL Global Development Group
10-15
type: SQL_IDENTIFIER
Note:
Name of the schema that contains the constraint
© 1996-2022 The PostgreSQL Global Development Group
7.4-9.6

cockroachdb

type: unknown
Note:
Name of the schema containing the constraint.
© 2022 CockroachDB
2-21.2
Note:
Name of the database that contains the constraint.
© 2022 CockroachDB
1-1.1

mssql

type: NVARCHAR(128) NULL
Note:
Name of schema that contains the constraint. ** Important ** only reliable way to find the schema of a object is to query the sys.objects catalog view.
© Microsoft 2022
azuresqldb-current-sql-server-ver15