`information_schema.constraint_table_usage.table_catalog`

mysql

type: SQL_IDENTIFIER NULL

Note:

Name of the database that contains the table that is used by some constraint (always the current database)

10-15

type: SQL_IDENTIFIER

Note:

Name of the database that contains the table that is used by some constraint (always the current database)

7.4-9.6

type: NVARCHAR(128) NULL

Note:

Table qualifier.