我怎样才能从coreData swift获得最近的用户聊天

I have two entities Friend and Message now i want to get the latest message of friend how can i do this

我有两个实体朋友和消息现在我想得到朋友的最新消息我该怎么做

Friend contain these things

朋友包含这些东西

Friend{
  name:String
  id:Int
  email:String
}

and Message Contain these thing and also have one to many relationShip from friend to message

和消息包含这些东西，并且还有从朋友到消息的一对多关系

   Message{
     id:String
     text:String
     created_at:Date
     /...// and many things

}

1 个解决方案

#1

You can get the latest message of user by sort Descriptor like this:-

您可以通过排序描述符获取用户的最新消息，如下所示： -

let fetchRequest = NSFetchRequest<Message>.init(entityName: "Message")
fetchRequest.sortDescriptors = [NSSortDescriptor.init(key: "created_at", ascending: false)]
let predicate = NSPredicate.init(format: "friend.id = %@","1")// pass the id of friend for you want to access latest message
fetchRequest.predicate = predicate

now you can fetch this request

现在您可以获取此请求

#1