Question

如何使用带有NSPredicate的NSBatchDeleteRequest从CoreData中删除行。

我想删除超过30天的记录。

我不想获取内存中的所有数据，而不是比较和删除，我想使用NSBatchDeleteRequest，就像我们在NSBatchUpdateRequest中一样。

以下是我编写的代码

let date = NSDate(); let yesterday = date.dateByAddingTimeInterval(-24*60*60); let predicate = NSPredicate(format: "date > %@", yesterday);
    let fetchRequest = NSFetchRequest(entityName: "Notification");
    let batchDelete = NSBatchDeleteRequest(fetchRequest: fetchRequest)

请快速给出答案

Answer 1

这是一个简单的例子。使用过滤您的请求的NSPredicate可以丰富。

let calendar = NSCalendar.currentCalendar()

let thirtyDaysAgo = calendar.dateByAddingUnit(.Day, value: -30, toDate: NSDate(), options: []) 

let fetchRequest = NSFetchRequest(entityName: "Notification")

fetchRequest.predicate = NSPredicate(format: "(date >= %@)", thirtyDaysAgo)

let deleteRequest = NSBatchDeleteRequest(fetchRequest: fetchRequest)

do {
  try context.executeRequest(deleteRequest)
  try context.save()
} catch {
  print (error)
}

NSBatchDeleteRequest与NSPredicate在swift中

1 个答案: