获取超过1000时，核心数据碰撞对象

Question

当我试图从核心数据获取超过1000个NSManagedObjects，我的应用程序崩溃与此消息：

error: (1) I/O error for database at .../Documents/Stores/Model.sqlite. 
SQLite error code:1, 'Expression tree is too large (maximum depth 1000)' 
CoreData: error: (1) I/O error for database at .../Documents/Stores/Model.sqlite. 
SQLite error code:1, 'Expression tree is too large (maximum depth 1000)' 

我用它来获取由用户选择的对象的代码是这样的：

NSManagedObjectContext *context = cdh.context; 
NSFetchRequest *request = [[NSFetchRequest alloc] init]; 
NSEntityDescription *entity = [NSEntityDescription entityForName:@"Spot" inManagedObjectContext:context]; 
NSError *error = nil; 
[request setEntity:entity]; 
request.includesPropertyValues = NO; 

NSMutableArray *subPredicatesArray = [NSMutableArray array]; 

for (NSString *string in uuidStrings) 
{ 
    NSPredicate *predicate = [NSPredicate predicateWithFormat:@"%K like %@", @"sID", string]; 
    [subPredicatesArray addObject:predicate]; 
} 

NSCompoundPredicate *compoundPredicate = [NSCompoundPredicate orPredicateWithSubpredicates:subPredicatesArray]; 
[request setPredicate:compoundPredicate]; 

NSArray *fetchedObjects = [context executeFetchRequest:request error:&error]; 

有没有更好的方式来获取1000+对象，这将不会导致我的应用程序崩溃？

Answer 1

假设uuidStrings包含了sID属性完全匹配项，你应该能够用这种（未经测试），以替换代码：

// remove subPredicatesArray, the loop and compoundPredicate 

NSPredicate *predicate = [NSPredicate predicateWithFormat:@"sID IN %@", uuidStrings]; 
[request setPredicate:predicate];