如何在Swift中组合两个CoreData谓词?

open func getAllCarsCount(from garages: [Garage], with categories: Set<Category> = []) -> Int {
    var returnCount = 0
    let context = DBContext.defaultContext

    var predicates = [NSPredicate]()
    for category in categories {
        let predicate = NSPredicate(format: "SUBQUERY(carHasCategories, $c, $c.categoryName == %@ ).@count > 0", category.categoryName)
        predicates.append(predicate)
    }

    for garage in garage {
        let predicate = NSPredicate(format: "garageNbr = \(garage.garageNbr) AND active = 1" )
        predicates.append(predicate)
    }

    let request = NSFetchRequest<NSFetchRequestResult>(entityName: "Car")
    request.predicate = NSCompoundPredicate(orPredicateWithSubpredicates: predicates)

    do {
        let count = try context.count(for: request)
        returnCount += count
    } catch let error as NSError {
        print("Could  not get all cars count. ", error.localizedDescription)
    }

    return returnCount
}

我想弄一些车,其中一辆 categories 但我需要组合两个谓词。所以我想要的是:

把所有的车都算上 garages 他们在哪里 active , garageNbr 匹配并且具有给定类别之一的。目前我的代码不能正常工作,如果有人能帮助我,我将不胜感激

数据库结构如下所示:

Garage , name 积极的

Car : 名称

Category categoryName

他们有关系:

: 关系: garageHasCars 目的地: 小型车 carInGarage

小型车 : 目的地: 车库 车库有汽车

Relationship: `carHasCategories`
Destination: `Category`
Inverse: `categoryHasCars`

类别 : 关系: categoryHasCars 目的地: 小型车 carHasCategories