Question

当我尝试从Core Data中获取超过1000个NSManagedObjects时，我的应用程序崩溃了这条消息：

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)'

我用来获取用户选择的对象的代码是：

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];

有没有更好的方法来获取1000多个不会导致我的应用崩溃的对象？

Answer 1

假设uuidStrings包含sID属性的完全匹配项，您应该可以使用此代码替换代码（未经测试）：

// remove subPredicatesArray, the loop and compoundPredicate

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

获取超过1000个对象时，核心数据崩溃

1 个答案: