C#•2y ago

How to add data into one-to-one relationship

Hello world!
I'm junior c# developer whose inmediate task is create a function that add Students and Teacher into one Subject. But I dont know where Can I start.

Lets' see the Subject model:

And this is the Teacher Model:

I must to mention that the project methodology is TDD, so I have to unit test first and later refactor if previus step are ok. But the problem is I dont know how could I test this function

So, if anyone could help me with a advice or link documentary, Id be really grateful!

Jimmacle•1/4/24, 10:17 PM

why is there mixed usage of

Nullable<T>

Nullable<T>

and

T?

T?

Angius•1/4/24, 10:17 PM

wtf

linqisnice•1/4/24, 10:17 PM

Create subject, create student, put student in subject.Students, create teacher, put teacher in subject.Teacher

linqisnice•1/4/24, 10:17 PM

then add to dbcontext

Angius•1/4/24, 10:18 PM

Also, the teacher can just not have a name?

Jimmacle•1/4/24, 10:19 PM

but yeah the answer to your question is simply assign the subject's teacher or add the subject to the teacher's subjects collection

Jimmacle•1/4/24, 10:19 PM

normal OOP things

Angius•1/4/24, 10:19 PM

Regardless, yeah

JJimmacle why is there mixed usage of `Nullable<T>` and `T?` <:thonk:491486269751164929>

GABRIEL22OP•1/4/24, 10:20 PM

I dont know this is the model I've got. I doubt the value is undefined

Angius•1/4/24, 10:20 PM

Got it from a teacher, I'd bet?

AAngius Regardless, yeah ```cs var student = new Student(); var teacher = new Teacher();...

GABRIEL22OP•1/4/24, 10:21 PM

This is how I did: public IHttpActionResult EnrollTeacher(string id)
> {
>
> var subject = _repo.GetById(id);
> var teacher = _repo.GetTeacherbyId(id);
>
> if(_repo.teacherCount() > 1 && subject != null)
> {
> Console.WriteLine("Teacher already set up");
> } else
> {
> subject.TeacherId = teacher.id;
> }
>
> return Ok(subject);
>
}

Jimmacle•1/4/24, 10:21 PM

repos on top of ef core Harold

linqisnice•1/4/24, 10:22 PM

dont check teachercount, you cant add more than one teacher anyway in that model above lol

linqisnice•1/4/24, 10:22 PM

its just one property not a collection

Angius•1/4/24, 10:22 PM

Was about to say, a subject has a single teacher

Angius•1/4/24, 10:22 PM

There shouldn't even be a (why is it camelCase btw) method there

Angius•1/4/24, 10:23 PM

Unless... it counts all teachers in the db?

Angius•1/4/24, 10:23 PM

But if so, then what would be the relevance?

linqisnice•1/4/24, 10:23 PM

also youre not adding anything to the db here

AAngius There shouldn't even be a `teacherCount()` (why is it camelCase btw) method ther...

GABRIEL22OP•1/4/24, 10:25 PM

Yes, a Subject has a single teacher, and I establish a Count function to check if a Subject already contain a Teacher, if is not, then it add the Teacher into Subject. But the problem is I'm not sure if I did ok nor how to unit test it,

Jimmacle•1/4/24, 10:25 PM

but that count function doesn't seem to have any relation to checking a specific subject/teacher/etc

GGABRIEL22 Yes, a Subject has a single teacher, and I establish a Count function to check i...

Angius•1/4/24, 10:26 PM

Why did I know that such garbage can only be created by a teacher KEKW

linqisnice•1/4/24, 10:26 PM

there is no need to count, you are not working with a collection of teachers

AAngius Why did I know that such garbage can only be created by a teacher <:KEKW:9560626...

GABRIEL22OP•1/4/24, 10:27 PM

Do I substract the nullable property? I know a Id couldn't be undefined.

linqisnice•1/4/24, 10:27 PM

you check if teacher is null, if its null, add teacher, if its not null, check if you are allowed to replace the teacher

linqisnice•1/4/24, 10:27 PM

thats it

Angius•1/4/24, 10:27 PM

A property should be nullable only and only every if the value can, actually, be null

Angius•1/4/24, 10:27 PM

If a teacher can just not have a name, sure, the name property should be nullable

linqisnice•1/4/24, 10:27 PM

only reason i made ids nullable in my entity models is for cascade deletes

Angius•1/4/24, 10:27 PM

If the teacher has to have a name, it should not be

Llinqisnice there is no need to count, you are not working with a collection of teachers

GABRIEL22OP•1/4/24, 10:28 PM

But, in the Controller, the way I add the teacher into Subject is fine? Or should I approach it another way?

linqisnice•1/4/24, 10:28 PM

you should literally just get the subject, add the teacher and the students normally

linqisnice•1/4/24, 10:28 PM

like regular c# code

linqisnice•1/4/24, 10:29 PM

like zzz showed you above

Angius•1/4/24, 10:29 PM

We're working within the constraints of, what seems like, a god-class kind of a repository

Angius•1/4/24, 10:29 PM

So anybody's guess ¯\_(ツ)_/¯

Llinqisnice you should literally just get the subject, add the teacher and the students norm...

GABRIEL22OP•1/4/24, 10:29 PM

Without Id in the way, and just with number of teacher and that stuff?

Angius•1/4/24, 10:29 PM

Subjects and teachers seem come from the same repo

linqisnice•1/4/24, 10:30 PM

just scrap the repo lol

GGABRIEL22 Without Id in the way, and just with number of teacher and that stuff?

Angius•1/4/24, 10:30 PM

With plain EF:

Angius•1/4/24, 10:31 PM

If you must, wrap it up in a repository method

AAngius Subjects and teachers seem come from the same repo

GABRIEL22OP•1/4/24, 10:31 PM

How can I unit test this function? I have to unit first test.

Angius•1/4/24, 10:32 PM

Uh, you can't really unit test EF without, idk, using a test database, or mocking the dbcontext

GABRIEL22OP•1/4/24, 10:32 PM

I'm using a In-Memory database.

Angius•1/4/24, 10:33 PM

How are you unit testing ?

Angius•1/4/24, 10:33 PM

You'd do it similarly, ig. Call the repository method, see if it made the appropriate changes to the db

Angius•1/4/24, 10:33 PM

I never used god-class repositories, nor did I ever unit test them, so I probably won't be of much help

Angius•1/4/24, 10:34 PM

Someone with more experience with, uh, enterprise (derogatory) kind of code would be more helpful here

AAngius You'd do it similarly, ig. Call the repository method, see if it made the approp...

GABRIEL22OP•1/4/24, 10:36 PM

Thank you for the help! I'm going to make the changes you suggest me.