使用parse和iOS SDK检索相关数据 [英] Retrieve related data with parse and ios sdk

问题描述

我只是想使用Parse将相关数据检索到我的应用程序中，但是遇到了一些问题. 我有2个表格，旅行和城市，旅行有一个相关的字段，称为origin-city.我在数据浏览器中使用了一个指针来将它们关联起来.

I'm just trying to retrieve related data into my app with Parse but I'm getting some problems. I have 2 tables, Travel and City, Travel has a related field called origin-city. I'm using a pointer in Data Browser to relate both of them.

所以我正在使用 queryForTable 方法

- (PFQuery *)queryForTable {
    PFQuery *query = [PFQuery queryWithClassName:self.parseClassName];
    [query includeKey:@"origin-city"];
    return query;

}

我总是得到指针ID，但没有得到我真正需要的城市名称. 这是执行此操作的正确方法吗?我如何获取城市名称?

And I'm always getting the pointer Id but not the City name that's what I really need. This is the proper method for doing this ? how could I retrieve the name of the city ?

修改

当我打印来源城市时，我会得到 City:M0PwR0OiLj:(null)，其中M0PwR0OiLj是City的objectId，在这里我需要名称

When I print the origin city I'm getting City:M0PwR0OiLj:(null) where M0PwR0OiLj is the objectId for City, here I need the name

非常感谢

推荐答案

我假设您使用的是PFQueryTableViewController，因为方法queryForTable属于该方法.指出查询已在进行中的错误是因为PFQTVC在后台触发了查询，因此在您的情况下无法进行findObjectsInBackgroundWithBlock回答.

I assume you are using a PFQueryTableViewController, as the method queryForTable belongs to that. The error stating that a query is already in progress is because the query is fired behind the scenes by the PFQTVC, so the answer asking to do a findObjectsInBackgroundWithBlock is not possible in your case.

使用此特殊的表视图控制器，还向cellForRowAtIndexPath传递了PFObject，这是与行匹配的对象.

With this special table view controller, the cellForRowAtIndexPath is also passed a PFObject, which is the object to matching the row.

要获取来自相关对象的城市名称，请在cellForRowAtIndexPath中使用以下代码:

To get the city name, which is from related object, you use this code in cellForRowAtIndexPath:

PFObject *city = object[@"origin-city"];
[cell.textLabel setText:city[@"name"]; // The name column from the City class

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