Cocoa Core Data efficient way to count entities

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滥情空心
滥情空心 2020-11-30 16:45

I read much about Core Data.. but what is an efficient way to make a count over an Entity-Type (like SQL can do with SELECT count(1) ...). Now I just solved this task with s

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  •  予麋鹿
    予麋鹿 (楼主)
    2020-11-30 17:43

    If you want to find count for specific predicated fetch, i believe this is the best way:

    NSError *err;
    NSUInteger count = [context countForFetchRequest:fetch error:&err];
    
    if(count > 0) {
    NSLog(@"EXIST"); 
    } else {
    NSLog(@"NOT exist");
    }
    

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