使用objectid解析ios wherekey [英] Parse ios wherekey using objectid

问题描述

在Parse的"Message"表中，有一个称为对话"的字段，它是pointer到Conversation(数据库中的另一个表)的字段.

In my "Message" table in Parse I have a field called conversation, which is a pointer to a Conversation (another table in my database).

要查询Message，我可以这样做:

To query for a Message, can I do:

    PFQuery *messageQuery = [PFQuery queryWithClassName:@"Message"];
    [messageQuery whereKey:@"conversation" equalTo:_conversation.objectid];
    [messageQuery findObjectsInBackgroundWithBlock:^(NSArray *objects, NSError *error) {

          ...

    }];

还是我必须获取实际的PFObject * myConversation并使用它...

or do I have to get the actual PFObject *myConversation and use that...

    PFQuery *messageQuery = [PFQuery queryWithClassName:@"Message"];
    [messageQuery whereKey:@"conversation" equalTo:myConversation];
    [messageQuery findObjectsInBackgroundWithBlock:^(NSArray *objects, NSError *error) {

          ...

    }];

似乎#1不起作用，但是#2起作用...我的问题是我怎样才能使#1起作用(即，当我有一个指针字段时，使用PFObject的ID进行查询)

It seems that #1 doesn't work, but #2 does...my question is how can I get #1 to work (i.e. use a PFObject's id to query when I have a pointer field)

推荐答案

.objectId只是一个字符串，如果您的对话"键包含指向myConversation的指针，则必须在等号中包含PFObject.

.objectId is just a string, if your "conversation" key contains a pointer to myConversation, then you must include a PFObject in the equal to.

如果只有objectId，则可以使用以下命令搜索没有数据的指针:

If you only have the objectId, you can search pointers without data using:

PFObject * myConversation = [PFObject objectWithoutDataWithClassName:@"Conversation" objectId:_conversation.objectid];

// continue here

[messageQuery whereKey:@"conversation" equalTo:myConversation];
[messageQuery findObjectsInBackgroundWithBlock:^(NSArray *objects, NSError *error) {

      ...

}];

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