ios - RealmSwift 查询中带有内部对象引用的谓词问题

Question

我有一个 Report 类，例如:

class Report: Object{

   @objc dynamic var id : String? = nil
   @objc dynamic var studentProfileId : String? = nil
   @objc dynamic var createdAt : String? = nil
   @objc dynamic var updatedAt : String? = nil
   @objc dynamic var type : String? = nil
   @objc dynamic var status : String? = nil
   @objc dynamic var assessment : AssessmentLocal? = nil
   var avgScore = RealmOptional<Double>(0)
}

Report类有一个AssessmentLocal类的评估变量。

class AssessmentLocal: Object{

   @objc dynamic var id : String?
   @objc dynamic var status : String?
   @objc dynamic var type : String?
   @objc dynamic var code : String?
   @objc dynamic var cycle = 0
   var year = RealmOptional<Int>(0)
   @objc dynamic var startDate : String?
   @objc dynamic var grade : String?
}

我正在尝试使用以下谓词进行查询:

let predicate = NSPredicate(format: "studentProfileId = %@ AND assessment.year = %@ AND assessment.cycle >= %@", report.studentProfileId!, String((report.assessment?.year.value)!), String((report.assessment?.cycle)!))

let reports = getDatabase().objects(Report.self).filter(predicate).sorted(byKeyPath: "assessment.cycle")

每当我尝试获取已保存的报告时，我都会崩溃。

"terminating with uncaught exception of type NSException".

我无法弄清楚这一点。

Answer 1

错误的发生可能是因为您的类型与 Realm 期望的类型不同。

assessment.cycle 和 assessment.year 是整数，因此您不应使用 %@ 作为它们的占位符。 %@ 用于字符串。对于整数，您应该使用 %i。

您还应该删除参数中的字符串转换。

let predicate = NSPredicate(format: "studentProfileId = %@ AND assessment.year = %i AND assessment.cycle >= %i", 
                            report.studentProfileId!, 
                            report.assessment?.year.value!, 
                            report.assessment?.cycle!
                            )