Why I Can't Access My 3Rd Level Coredata Data in Swift

why I can't access my 3rd level CoreData data in swift?

The temas property is a NSOrderedSet, and the subscript [0] returns the
type AnyObject. So (as already said in a comment) you have to cast the AnyObject
to the actual type

let curso = cursos[index]
println(curso.nombre)
let firstTema = curso.temas[0] as Tema
println(firstTema.nombre)
let firstSubTema = firstTema.subTemas[0] as SubTema
println(firstSubTema.nombre)

Note that you can simplify your loop using for - in:

for curso in cursos {
    // ...
}

and recursively enumerating all objects would look like

for curso in cursos {
    println(curso.nombre)

    for tema in curso.temas.array as [Tema] {
        println(tema.nombre)

        for subtema in tema.subTemas.array as [SubTema] {
            println(subtema.nombre)
        }
    }
}

Core Data error when fetching

You probably changed your managed object model in Xcode, but you have still installed app on your device/simulator with older data model configuration.

That's why you getting this error.
If your app is brand new and you don't have to bother with compatibility to already installed apps, you can just erase old app from the device/simulator and install new one.

If you need to keep compatibility of older data model configuration with newer one, you should use versioning of the model and make all your changes in the newer data model version.

Why Xcode does not show index options for CoreData entities and attributes?

As @tomharrington said, the solution is in the WWDC 2017 video: Indexing stuff begins at 10:32 and the demo at 16:40.

It's still possible to create and index via Xcode9:

• First, select your entity, long-click on the + (Add Entity), and select Add Fetch Index.

• Then, name your index appropriately, the select the property you want to index on (and choose ascending or descending, depending on how is organized your data)
  

• Finally, as explained on the video, this will not trigger a migration and user that update your app will not get your index. If you want to force a model migration, add an Hash Modifier by selecting the entity, and setting Right Panel > 3rd tab > Versioning > Hash Modifier.
  

Saving CoreData to a Web Server with Swift 3.0

The question that you have linked is not trying to explain how to communicate with a web server. It is explaining how to store data in core data and tag/mark it in a way that you know which records have been sent to the web server or not.

So the Predicate will fetch all records that have not been sent to the web server and allow you to send them when you have an internet connection available.

Communicating with a web server can be a broad topic and will depend on your web server and API setup, so it is too much to explain here fully. I refer you to some free online resources that will help you understand networking in Swift.

• Udacity - Networking with Swift
• Ray Wenderlich - Alamofire Tutorial
• Stack Overflow - Swift POST Request

Here is an example of a POST Request from the StackOverflow answer above

var request = URLRequest(url: URL(string: "http://test.tranzporthub.com/street45/customer_login.php")!)
request.httpMethod = "POST"
let postString = "user_id=chaitanya3191@gmail.com&password=123"
request.httpBody = postString.data(using: .utf8)
let task = URLSession.shared.dataTask(with: request) { data, response, error in
    guard let data = data, error == nil else {                                                 // check for fundamental networking error
        print("error=\(error)")
        return
    }

    if let httpStatus = response as? HTTPURLResponse, httpStatus.statusCode != 200 {           // check for http errors
        print("statusCode should be 200, but is \(httpStatus.statusCode)")
        print("response = \(response)")

    }

    let responseString = String(data: data, encoding: .utf8)
    print("responseString = \(responseString)")
}
task.resume()

Using code similar to this, you should be able to send data to your web server, then your web server can do whatever it likes with it.

UPDATE:

To encode your parameters to JSON you can use the following code as a guide

var dictionary = [
    "username": "Test User",
    "password": "Password"
]

if let jsonData = try? JSONSerialization.data(withJSONObject: dictionary, options: []) {
    // jsonData is a byte sequence, to view it you would need to convert to string
    print(String(bytes: jsonData, encoding: String.Encoding.utf8))
}

Which would output:

Optional("{\"username\":\"Test User\",\"password\":\"Password\"}")

Note: you would send it as data, not the string version. so your code might look like this:

request.httpBody = jsonData

Exception on Core Data save

NONE is an alias for NOT ANY and is indeed for to-many relationships.
What you probably want is:

[NSPredicate predicateWithFormat:@"NOT name in %@", excludedTypes];

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