RealmSwift 查询中带有内部对象引用的谓词问题

Question

我有一份报告 class 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)
}

报告 class 有一个 AssessmentLocal class 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".

我想不通。

Answer 1

发生错误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。您应该对整数使用 %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!
                            )

Answer 2

你也可以这样做。

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

RealmSwift 查询中带有内部对象引用的谓词问题

Problem with predicates with inner object references in RealmSwift query

realm

ios

swift4