在IOS Realm主键中，如何更新数据，如果已经存在，则不应重复两次？

Question

使用primaryKey offerName如何避免重复两次或更多次数据。

[当我们使用该对象的didSelectAtRow时如何编辑它并将数据更新到其对象，而不是在更新时将其当作新对象。

我该怎么办？

import Foundation
import RealmSwift

class Discount: Object {

    @objc dynamic var offerName : String = ""
    @objc dynamic var percentage: Float = 0.00
    @objc dynamic var segmentIndex : Int = 0
    @objc dynamic var dateWise: Date?


    override class func primaryKey() -> String? {
        return "offerName"
    }

}

Answer 1

这是一个使用主键更新现有对象的代码片段

guard let realm = try? Realm() else {
    return
}
let discounts = realm.objects(Discount.self)
try? realm.write {
    discounts.forEach { $0.dateWise = Date() }
    realm.add(discounts, update: .all)
}

检查方法文档：

/**
 Adds all the objects in a collection into the Realm.

 - see: `add(_:update:)`

 - warning: This method may only be called during a write transaction.

 - parameter objects: A sequence which contains objects to be added to the Realm.
 - parameter update: How to handle
 without a primary key.
 - parameter update: How to handle objects in the collection with a primary key that alredy exists in this
 Realm. Must be `.error` for object types without a primary key.
 */
public func add<S: Sequence>(_ objects: S, update: UpdatePolicy = .error) where S.Iterator.Element: Objec