default Optional<? extends Table> findForeignTable() {
        final Optional<Schema> schema = ancestors()
            .filter(Schema.class::isInstance)
            .map(Schema.class::cast)
            .findFirst();

        return schema.flatMap(s -> s.tables()
            .filter(tab -> tab.getId().equals(getForeignTableName()))
            .findAny()
        );
    }
A helper method for accessing the foreign {@link Table} referenced by
this key.

@return the foreign {@link Table} referenced by this
runtime-parent/runtime-config/src/main/java/com/speedment/runtime/config/ForeignKeyColumn.java