ios - Result of Core Data query does not change when using a predicate to filter -

ios - Result of Core Data query does not change when using a predicate to filter -

i'm building core info project in objective-c. have 3 tables names: countryarea, chargestation , plugtype. have next relations.

countryarea<-->>chargestation<<-->>plugtype

data: area1<-->>chargestation1.hasplugtype<-->type1 && -->type2 area1<-->>chargestation2.hasplugtype<-->type1 && -->type3 area1<-->>chargestation3.hasplugtype<-->type2

i'm fetching table countryarea has to-many relation chargestation, has to-many relation plugtype. i'm trying exclude chargestations illustration contain plugtype.type == 'type2' if have multiple types shouldn't excluded predicate: station3 should excluded!

[nspredicate predicatewithformat:@"subquery(stations, $c, subquery($c.hasplugtype, $t,$t.type != %@).@count).@count > 0",@"type2"];

this returns same result if wasn't using predicate.

any help?

you want exclude chargestations have plugtype.type = "type", or equivalently "include chargestations count of (plugtypes type = "type2") zero". try:

[nspredicate predicatewithformat:@"subquery(stations, $c, $c.hasplugtype.type = %@).@count = 0",@"type2"];

ios cocoa-touch core-data nspredicate