swift3 - Realm Swift select all values which match one field in one-to-many relationship entity -


i have 2 entities in realm product , producttype. product has 1 many relation product type.

product entity 1 many

import foundation import realmswift  class product: object{     dynamic var productname = ""     let producttypelist = list<producttype>()  }

producttype entity

import foundation import realmswift  class producttype: object{      dynamic var typename: string = ""   dynamic var typelogourl: string = "" }

my goal select products, contains producttype typename, example "electronics". can easily, if there 1 one relationship this

product entity 1 one

import foundation import realmswift  class product:object{     dynamic var productname = ""     dynamic var producttype : producttype?  }

query example

let realm = try! realm() let producttypename = "electronics" let predicate = nspredicate(format: "producttype.typename == %@", producttypename) let rmproducts = realm.objects(product.self).filter(predicate)

any ideas how make query 1 many version of product class?

you have use subquery , check count of producttypes in list matching name bigger 0.

let rmproducts = realm.objects(product.self).filter("subquery(producttypelist, $type, $type.typename == %@).@count>0",producttypename)

i have run query on following test set , got expected results:

class product:object{     dynamic var productname = ""     var producttypelist = list<producttype>() }  class producttype  : object{     dynamic var typename: string = ""     dynamic var typelogourl: string = "" }  let types = [producttype(value: ["typename":"electronics","typelogourl":"url"]),producttype(value: ["typename":"a","typelogourl":"url"]),producttype(value: ["typename":"electronics","typelogourl":"a"]),producttype(value: ["typename":"b","typelogourl":"url"])]  let prod1 = product() prod1.productname = "a" prod1.producttypelist = list([types[0],types[1]]) let prod2 = product() prod2.productname = "b" prod2.producttypelist = list([types[3],types[1]]) let prod3 = product() prod3.productname = "c" prod3.producttypelist = list([types[2],types[1]]) var prod4 = product() prod4.productname = "d" prod4.producttypelist = list([types[1]])  try! realm.write {     realm.add(types)     realm.add([prod1,prod2,prod3,prod4]) }  let producttypename = "electronics" let predicate = nspredicate(format: "producttype.typename == %@", producttypename) let rmproducts = realm.objects(product.self).filter("subquery(producttypelist, $type, $type.typename == %@).@count>0",producttypename) print(rmproducts) //rmproducts contains prod1 , prod3 expected

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