使用prepareForSegue和使用Core Data传递数据之间有什么区别？

Question

Is there anything different between the two? I'm trying to figure out which one is better to use because they seem to do the same thing, or at least to me. I'm trying to pass data between multiple views.

Answer 1

Core Data is an object database that usually has an SQL relational database as it's backing store. It is used for storing and manipulating complex data-sets, and presenting them to the user.

PrepareForSegue is a method that gets called on a view controller before a new view controller is invoked from a segue. You can use prepareForSegue() as a way to pass data to the new view controller that is about to be displayed.

The two things have very little in common.

Since Core Data is a way to store app-wide persistent data, you can have multiple view controllers read and write data to a shared Core Data database, and in that way communicate information between view controllers, but that's about as far as the comparison goes.

To use an analogy, Core Data is a filing cabinet that everybody in an office has access to. If a clerk files some information in the filing cabinet, at any future time another employee can find that file and get the information, and so can anyone else in the company who has access to the cabinet. PrepareForSegue is a text message between 2 specific phone numbers. It transmits a burst of transient information, once and only once, between specific people.

EDIT:

There are other options for passing information between view controllers as well.

Check out this question/answer thread I created on the subject:

How do you share data between view controllers and other objects in Swift?

Answer 2

If you want the data to persist then you must use SQLite3, Core Data or something like realm.

If you just want to pass the data around from one viewController to another then you would do it through something like prepareForSegue

Answer 3

PrepareForSegue would be to pass (tempory) data between two viewControllers. CoreData is a library to allow you to store data inside your app and re-use it whenever you want wherever you want.

Answer 4

PrepareForSegue allows you to get a reference to the destination view so you can pass the variables you want.

override func prepareForSegue(segue: UIStoryboardSegue!, sender: AnyObject!) {
    let viewController = segue!.destinationViewController as ViewController
    //here you can access view variables as viewController.variable
}

CoreData instead allows you to persist data to a SQL Database, maybe not what you want.

But beware, you can only pass data from de origin view to the destination one.