If I create a table 'domains' in the default scheme and execute the update procedure of the schema tool, it will throw a PDOException (SQLSTATE: Cardinality violation: 7 ERROR: more than one row returned by a subquery used as an expression)
I've traced the error to the following statement, which is created by Doctrine\DBAL\Platforms\PostgreSqlPlatform->getListTableForeignKeysSQL():
This returns two oids because there are two relations with the name domains. One is my table and the other is a view in the information_scheme scheme.
The same problem should occur with the other information_scheme relations.