是否有更高效的内存搜索核心数据数据库？

I need to see if an object that I have obtained from a CSV file with a unique identifier exists in my Core Data Database, and this is the code I deemed suitable for this task:

我需要查看我从核心数据库中是否存在从具有唯一标识符的CSV文件中获取的对象，这是我认为适合此任务的代码：

NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] init];
NSEntityDescription *entity;
entity = 
[NSEntityDescription entityForName:@"ICD9"
            inManagedObjectContext:passedContext];
[fetchRequest setEntity:entity];
NSPredicate *pred = [NSPredicate predicateWithFormat:@"uniqueID like %@", uniqueIdentifier];
[fetchRequest setPredicate:pred];
NSError *err;
NSArray* icd9s = [passedContext executeFetchRequest:fetchRequest error:&err];
[fetchRequest release];
if ([icd9s count] > 0) {
    for (int i = 0; i < [icd9s count]; i++) {
        NSAutoreleasePool *pool = [[NSAutoreleasePool alloc]init];
        NSString *name = [[icd9s objectAtIndex:i] valueForKey:@"uniqueID"];
        if ([name caseInsensitiveCompare:uniqueIdentifier] == NSOrderedSame && name != nil)
        {
            [pool release];
            return [icd9s objectAtIndex:i];
        }
        [pool release];
    }
}
return nil;

After more thorough testing it appears that this code is responsible for a huge amount of leaking in the app I'm writing (it crashes on a 3GS before making it 20 percent through the 1459 items). I feel like this isn't the most efficient way to do this, any suggestions for a more memory efficient way? Thanks in advance!

经过更彻底的测试后，似乎这个代码导致我正在编写的应用程序中出现大量泄漏（它在3GS上崩溃，然后通过1459项目将其降低20％）。我觉得这不是最有效的方法，对于更有效的内存方式有什么建议吗？提前致谢！

2 个解决方案

#1

Don't use the like operator in your request predicate. Use =. That should be much faster.
不要在请求谓词中使用like运算符。使用=。那应该快得多。
You can specify the case insensitivity of the search via the predicate, using the [c] modifier.
您可以使用[c]修饰符通过谓词指定搜索的大小写不敏感性。
It's not necessary to create and destroy an NSAutoreleasePool on each iteration of your loop. In fact, it's probably not needed at all.
没有必要在循环的每次迭代中创建和销毁NSAutoreleasePool。事实上，根本不需要它。
You don't need to do any of the checking inside the for() loop. You're duplicating the work of your predicate.
您不需要在for（）循环中进行任何检查。您正在复制谓词的工作。

So I would change your code to be:

所以我会将你的代码改为：

NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] init];
[fetchRequest setEntity:...];
[fetchRequest setPredicate:[NSPredicate predicateWithFormat:@"uniqueID =[c] %@", uniqueIdentifier]];
NSError *err = nil;
NSArray *icd9s = [passedContext executeFetchRequest:fetchRequest error:&err];
[fetchRequest release];
if (error == nil && [icd9s count] > 0) {
  return [icd9s objectAtIndex:0]; //we know the uniqueID matches, because of the predicate
}
return nil;

#2

Use the Leaks template in Instruments to hunt down the leak(s). Your current code may be just fine once you fix them. The leak(s) may even be somewhere other than code.

使用仪器中的泄漏模板来搜索泄漏。修复后，您当前的代码可能会很好。泄漏甚至可能是代码之外的其他地方。

#1

Don't use the like operator in your request predicate. Use =. That should be much faster.
不要在请求谓词中使用like运算符。使用=。那应该快得多。
You can specify the case insensitivity of the search via the predicate, using the [c] modifier.
您可以使用[c]修饰符通过谓词指定搜索的大小写不敏感性。
It's not necessary to create and destroy an NSAutoreleasePool on each iteration of your loop. In fact, it's probably not needed at all.
没有必要在循环的每次迭代中创建和销毁NSAutoreleasePool。事实上，根本不需要它。
You don't need to do any of the checking inside the for() loop. You're duplicating the work of your predicate.
您不需要在for（）循环中进行任何检查。您正在复制谓词的工作。