All right, so now let's get all students from a specific university.
So let's create a new method, because we have seen multiple methods already to get data, to change
data, to set up data, to combine data.
And now let's just search for data.
So let's create a method called get all students from Yale, and you can try to build that or implement
that method yourself.
So pause the video if you feel like it.
All right.
So I'm creating a new variable called Students from Yale, and that will end up being a collection of
innumerable and from student in data context dot students.
I want to check where the student dot university dot name is equal to Yale and I want to select that
student.
So that's nothing too new.
The only thing that is different is that we had this in data context students and students at university
name that is slightly different to what we have seen so far, but that's pretty cool because now we
get a list of all the students who are at the University of Yale and with just this one line, well,
it's actually one line, but in this case, it's three lines.
All right.
So now if we want to set that as the item source, we can just set that up.
Item source will be students from Yale.
Now let's check out that method.
Let's run it in our main method here, our main window constructor.
And here it's get all students from Yale.
All right, now let's see what is displayed to us.
And we are the only two students.
It's Carla and Toni, because the other ones are at another university.
They are at the Beijing Tech University.
Right.
All right.
So there you are.
You see the ID, the name, the gender and the university ID, then student lecturers and university
as well, who are or which are empty.
But that's based on all of the other stuff that we have run.
All right.
So that's how you can get all students from Yale.
All right.
And now let's go ahead and create a new method, public void, get all universities with transgenders.
So let's say there is in whatever country there is a support for universities who will have transgenders
and then to get additional funds or something like that.
Then you would run this method and it will give you all the students who are transgender and will give
you even all the universities who have transgenders.
So that's the actual return that we get here.
So let's create a new variable here.
Trans gender universities who are from student in data context students.
So we want to have students first of all, but then we want to join them.
So we want to join university.
And here university
in and this one is an on capital one.
So I create a new value here, join university in data context universities and I apply that on student
university.
So here I join two tables with each other and then I check where the university, and then I check university
because here we're joining it right now.
I can go ahead and choose that and I can check where the student the gender is equal to transgender.
And I want to select.
And what do I want to select?
Well, I don't want to select the student this time.
I want to select the university this time.
All right.
So now.
I need to use a double exclamation equals sign because I'm comparing and not setting a value.
And now just to make sure that the trend gender is written correctly.
All right.
It seems correct.
So that's how I wrote it.
And now I can show that on my data grid.
So items source is going to be transgender universities.
All right.
So if we call that method here, get all universities with transgenders.
And if you run that, we see that only Beijing Tech has transgender students.
All right.
So that's how you can generally join tables and play around with them.
And yeah, you see, it's done with C-sharp.
Everything is done with C-sharp here.
And no SQL or SQL code that we have to write manually now was a little challenge for you.
We want to have all the lectures which are taught at Beijing Tech.
Okay.
I hope you tried it.
That one is also pretty tough.
So if you manage to do that great job, get all lectures from Beijing Tech.
Now let's see.
What do we need?
Well, we need a variable called lectures from Beijing Tech.
And I check from my.
Student lectures in data context student lectures.
I join student that and in the data context of student on to my sl dot student ID which equals the student
ID
where my student dot university name is equal to Beijing Tech.
So plenty of thinking here.
That's really a tough one.
So if you manage to do that, really, that's that's great because then you quite understood what we're
doing here, right?
So lecture as well, that lecture.
So generally, what are we doing?
And by the way, there are multiple ways to solve that.
It's best to maybe not solve that with one query, but in our case, we're just fine doing it.
All right, so we loop the relationship table between student and lecture and simply check if the associated
student is from Beijing Tech.
If yes, we select that Associated Lecture.
All right.
So this is, as I said, this is a more complex one.
And this is really just to show you that we can connect to tables that have quite a far distance from
each other.
And by far, I mean, they are not really that related to each other.
But we can still do this connection because what we are doing is we get all the lectures from a specific
university and if we check that here, this is lecture and this is university, and they are so far
away because university is only connected to student and lecture is only connected to student lecture,
but student lecture is connected to student.
And that's what we need to do here.
We need to join them in a way that we get all the information that is required.
So that's why this one is a rather tricky one.
And if you manage to do that, great.
And if you didn't, no worries.
Then in order to display those, we use it as the item source again, which will be lectures from Beijing
Tech.
Now let's call this method here, get lectures from Beijing Tech and now let's run the code.
And we are in Beijing Tech.
For some reason only history is taught.
And why is that?
So if we check it out what we have done so far.
So we have created Layla and who's female and Jane who are with transgender, and those two are at Beijing
Tech.
And the problem here is that Jane doesn't even have a lecture.
So we haven't assigned a lecture to Jane and we have only assigned a lecture to Leslie.
And if we check it out here lately, has the context.
It's somewhere here.
Leslie has only history.
So we have no student who learns or who has math as this lecture.
And that's why we don't have math at Tech University, which shouldn't happen.
Right?
So a tech university should definitely have math as their subject or as the lecture.
All right.
So now I'm just going to show you two more things.
And I think it's best if we do that in the next video.
So we will see how to update data and how to delete data.
So see you in the next video.