default Optional<? extends Column> findForeignColumn() {
        return findForeignTable()
            .flatMap(table -> table.columns()
                .filter(col -> col.getId().equals(getForeignColumnName()))
                .findAny()
            );
    }
A helper method for accessing the foreign {@link Column} referenced by
this key.

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