需要帮助斯威夫特滤芯数据3

Question

我似乎无法找到属于在斯威夫特滤芯数据的任何好的文档或教程3

我有以下代码：

let tempVar: String = "abcdef" 

let context = (UIApplication.shared.delegate as! AppDelegate).persistentContainer.viewContext 

do { 

    /* Need code to modify the fetchRequest, so that it only pulls results where the "projectID" field is equal to whatever is stored in the tempVar variable. */ 

    cstProjectDetails = try context.fetch(CSTProjectDetails.fetchRequest()) 
} catch { 
    print("There was an error fetching CST Project Details.") 
} 

基本上，我只是试图向fetchRequest添加一个简单的过滤器，以便它只从“cstProjectDetails”中提取结果，其中“projectID”字段等于先前设置的变量的内容（在本例中为“tempVar” ）。

任何想法？

编辑：选中的答案对我来说确实有效，但我不得不快速调整请求初始值设定项的代码。这里是我结束了代码：

do { 
    let request: NSFetchRequest<CSTProjectDetails> = CSTProjectDetails.fetchRequest() 
    request.predicate = NSPredicate(format: "projectID == %@", cstProjectID) 
    cstProjectDetails = try context.fetch(request) 
    print(cstProjectDetails) 
} catch { 
    print("There was an error fetching CST Project Details.") 
} 

Answer 1

您需要连接到请求的谓词：

let request = CSTProjectDetails.fetchRequest() 
request.predicate = NSPredicate(format: "projectID == %@", tempVar) 
cstProjectDetails = try context.fetch(request)