Question

我想知道如何从CloudKit表中获取第一条记录。例如，我有一个表＃34; Classes＆＃34;而且我只想获得上次修改的类，而不是像现在这样获得所有类：

let pred = NSPredicate(format: "Students CONTAINS %@", studentRecord)
var query = CKQuery(recordType: "Class", predicate: pred)
publicDB.performQuery(query, inZoneWithID: nil) {
    records, error in
    if error != nil {
        println("\(error)")
    } else {
        if records.count > 0 {
            for record in records {
                println("\(record)")
            }
        }
    }
}

Answer 1

嗯，您需要为您的特定场景做两件事。

在＆＃34;修改＆＃34;上添加排序这是每个记录上Apple生成的字段。
您需要使用CKQueryOperation对CKQuery强制使用LIMIT。

您的代码应如下所示：

let pred = NSPredicate(format: "Students CONTAINS %@", studentRecord)
var query = CKQuery(recordType: "Class", predicate: pred)
let sort = NSSortDescriptor(key: "Modified", ascending: false)
query.sortDescriptors = [sort]
var queryOperation = CKQueryOperation (query: query)
queryOperation.resultsLimit = 1
queryOperation.recordFetchedBlock = {
    record in
    println("\(record)")
}
queryOperation.queryCompletionBlock = {
    queryCursor, error in
    if error != nil {
        println("\(error)")
    }
}
publicDB.addOperation(queryOperation)

CloudKit仅获取第一个记录

1 个答案: