Swift NSFetchedResultsController忽略NSPredicate

Question

我现在正在调试以下代码几个小时。

对我来说，看起来我的NSPredicate被忽略了。 我在核心数据库中有2个条目。无论我设定什么谓词，我总是回到这两个条目。两者都有一个名为type的属性为1.即使我将谓词设置为(type == 5)，也会获取相同的2个条目。

    // MARK: - Fetched results controller

var fetchedResultsController: NSFetchedResultsController {
    if _fetchedResultsController != nil {
        return _fetchedResultsController!
    }


    let fetchRequest = NSFetchRequest()
    // Edit the entity name as appropriate.
    let entity = NSEntityDescription.entityForName("Item", inManagedObjectContext: self.managedObjectContext!)
    fetchRequest.entity = entity

    // simply ignores verything here...
    // -----------------------------------------------
    // I can use (type == 5) whereby the db only contains items with type == 1...
    // It's like the predicate is nevery used in the fetchrequest.
    fetchRequest.predicate = NSPredicate(format: "(name LIKE '%Eier%')")!
    println(fetchRequest.predicate)

    // Set the batch size to a suitable number.
    fetchRequest.fetchBatchSize = 20

    // Edit the sort key as appropriate.
    let sortDescriptor = NSSortDescriptor(key: "date", ascending: false)
    let sortDescriptors = [sortDescriptor]

    fetchRequest.sortDescriptors = [sortDescriptor]

    let aFetchedResultsController = NSFetchedResultsController(fetchRequest: fetchRequest, managedObjectContext: self.managedObjectContext!, sectionNameKeyPath: nil, cacheName: "Main")
    aFetchedResultsController.delegate = self
    _fetchedResultsController = aFetchedResultsController

    var error: NSError? = nil
    if !_fetchedResultsController!.performFetch(&error) {
        abort()
    }

    return _fetchedResultsController!
}
var _fetchedResultsController: NSFetchedResultsController? = nil