php - In Propel2, filter crossref by null value -
i use propel2 orm. i've 2 tables entry , category connected many-to-many relationship via entrycategory table. i set iscrossref on true in schema.xml. everything works fine : i'm able filter entry category : entryquery::create()->filterbycategory($cat) but i'm not able filter entries with no category . tried entryquery::create()->filterbycategory(null, criteria::equal) or entryquery::create()->filterbycategory(null, criteria::isnull) but, gives me 'filterbycategory() accepts arguments of type \category or collection' i tried entryquery::create()->where('category null') but, i've got error unknown column 'category' in 'where clause' so, need ... edit : extract of schema.xml : <?xml version="1.0" encoding="utf-8"?> <database package="core" name="bank" identifierquoting="true" defaultidmethod="native" defaultphpnamingm