Currently the table parameter is mandatory:
I think it would be useful to return the exported keys for all tables if the parameter is null. We could also allow a search pattern (using LIKE):
As a workaround it's possible to send N queries to retrieve the exported keys for N tables but it's detrimental (performance wise).
We might need to do the same for MariaDbDatabaseMetaData#getImportedKeys to be consistent.
Interestingly, it's already possible to retrieve the primary keys for all tables using MariaDbDatabaseMetaData#getPrimaryKeys.