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Gay guys falling or previous activity of having already to model to our project we will no proceed to

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starts running queries to collect data from our database and somehow present it in our application.

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So our first activity is to deal with well existing data so we know we have data in our table we put

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it there in the types of cars table where we have for cars to be selected from and the objective here

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is to modify our list for the dropdown box then bind it directly to what is coming from the database.

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So I went into the design I went to edit items and I know there is nothing inside of type of car that

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is empty and this does verify how empty it is.

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So I'm looking at the application itself and you see there is nothing in there.

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So the expectation is that after all our operation we will see the cars in there.

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All right so let me just close that go over to the code behind and then we can get started.

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So the first thing that I want to do is create an object that represents our data model.

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So remember I said that there is a few names here that we need to know strictly.

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Those are properties and then that we need to know the name of our entity container which is car into

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entities right.

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So in the code behind on the public partial on the right side of the control the constructor sorry.

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I'm going to enter private and say Read only some declaring an object of type.

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Car rental entities.

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So this object embodies this entire space is entire space that you're looking at the entire diagram

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every entity represented in the diagram is encapsulated by the type car rental entities.

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So by making reference the car into entities giving it an object name some want to call the car into

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entities that come on C and I to just do semicolon and then so this object is going to give me access

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to every single entity that is inside of my model or every table that's I would inserted into the model.

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All right.

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So Mark in the code behind the next thing I want to do is actually initialize it.

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So this is a declaration but it's not initialized right.

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No this is no right.

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So I'm just going to see car are into entities is equal to a new instance off and car or into entities.

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Please note var wouldn't work here.

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You can declare parts of a class as var All right.

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So you can do variables as var we can do properties of class as var.

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So this is a private property of our farm.

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All right.

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So once again we've declared a private property of type Car Into entities car into entities being the

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name of our entire database model.

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All right.

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And then I give you the object name with the same name.

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This would come on see and here in the constructor I'm just initializing it to a new instance.

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So it's no longer No it's agreed to because no it's not being used.

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But don't worry about that just yet.

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All right.

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The next thing I need to do is to figure out how is it I'm going to retrieve the data from the database

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so that it is present by the time the form comes up.

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So the expectation is that when I open this application the form loads and it will load with the drop

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down list fully equipped with the data it needs to care of operation.

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So that means I need to query the database get the information from the database have it presented in

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the form all of that by the time you will the user would be ready to click the dropdown box.

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So I'm going to add what we call a farm load events I'm just clicking the form.

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Notice I think farm and the box sets off or the canvas itself is selected and then I go to properties.

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The lightning bolts and I'm going to look for the Load event.

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See.

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So I want something to happen when the farm is loaded.

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So when the farm loads I want to run that query very quickly.

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All right.

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So I want to generate a formal event.

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I'm just into the thinking that I need seeing farm one on the score load.

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So then seeing what do you want to happen when the farm loads.

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So when the farm loads once again I want to query the database someone to say something.

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Var cars is equal to so I'm declaring some variable called var I'm calling it cars are sorry.

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Some variable of type.

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Var calling it cars.

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And then I need to assign something to it.

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And what I intend to assign to it is records from the database from the table types of cars.

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So when I declared this entity up top here are these objects rather of type Car Into entities.

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This represents my database so I can then see car rental entities and then use my dots because it's

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an object so I can use my dot upwards as to see the properties therein.

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And then when I say dot you'll notice that I have my table being made references of car rental records

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if I go back to my database and look car into the red card was the name of the table but then it has

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many records.

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So that's one of the things the month the model does by default do try some plural lies the table names

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because I mean I call it it's a table name car into a record but it's really a car into our records

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system.

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So I really should have called a car into our records but that's beside the point.

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The fact is that using my dot operates I can access this table.

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So that's on the table I want.

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Do I want type types of cars.

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All right.

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And then I want this in the form of at least someone to see not to list open and close parentheses.

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And so what this is doing is using a language or mechanism we call a link.

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So it's an easy to see sharp but the library of is called the link and it is a nice way to query your

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database using need to see sharp code.

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So once again I would of basically established an instance of a connection to my database through the

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declaration of this property.

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I initialized it in the constructor so that's all constructors are for the initialized.

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Things are initialize see initialize component there will initializing my database to a new instance

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and then when I want to call in the database I use that object that was previously declared and initialized.

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I use my dot operator and then I can access my table and then basically that's it.

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So if you're used to that literally that's it.

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And I'm just converting into all of these.

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So on a specific date that I have called a C sharp at least and that is why I have the list.

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So if you use the database development this is the same thing as seeing select star from types of cars.

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But then this is askew.

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This is not native C sharp so to be able to write this kind of obscure would've taken far more lines

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and you know I would love to initialize a data reader than a data table to call it the objects and a

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bunch of things but link makes it so easy because you just call the database model.

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Call the table and then if you want it in a list you just say so it is then it's easier to just say

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to list because that's a more universal data type and it's easier to maneuver with.

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So now that we have the list of cars stored instead of for variable cars we need to put it to use so

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what I want to do once again is when the farm loads which is going to fire this event we want to get

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the list of cars from the database and then have the combo box display them.

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All right.

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So the next step is to say call our combo box at a CB type of car right.

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And then we're going to see display members.

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So there are two properties that we're going to set.

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First we want to set the display member and that's who's going to be equal to name.

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So display members it takes that you will see it.

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So remember that when we had it set up the we setting the items and you would see that takes Tondo you

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would see that takes Toyota etc display a member is the takes that you see.

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And so if you look back at your database design you would notice that the idea is one two three four

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you don't want the person to be seeing one two three four that means nothing to them.

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But the takes that you want them to see is the name Honda Lada buggy Toyota.

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Right.

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So name is the display a member and the value that we're interested in would be the idea.

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So we have volume member.

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Display a member and you have value member because it's actually the value that we want to store not

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the display.

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Once again we have a car into our card that has a type of car idea of type int which means we only want

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to store the idea associated to the type of car we don't need to know the name again because that's

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why we created the table to just store the names and the I.D..

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So once we make reference to that I.D. from the car into our record we can look back and see that oh

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if it was eighty three then we know it's buggy or the person selects buggy we want to store I.D. three

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on the red card.

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All right.

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So the volume member would be what you intend to really store and that's in the background.

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Right.

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And then after sitting those two I am going to see that the data source for the items to be put into

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the combo box so that CB type of card data source is going to be equal to cars.

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So let's go through this again.

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I'm querying the database for the list of cars and then I'm saying that I want my combo box whatever

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data source it gets lots of little bits of data gets does look for a display a member for a name set

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the volume member to be I.D. and then said the data source to be the cars.

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So and I get the list of cars they're all coming over with I.D. and name someone to display the name

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and when to store the I.D. And I'm going to set that this list of cars with I.D. and name should be

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the source for the list of items coming into this combo box.

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So let's start and see how that works.

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And voilà.

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So now you're seeing a list of items for our farm or for our drop though and sermon by cutting them

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out earlier.

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So loaded.

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There was nothing in there so you're seeing that data is actually in there and this data is going directly

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from the database.

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And to prove that I want to close that window go to the database.

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Add one more car.

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So we added one more car to our fleet.

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And this one is a Subaru.

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All right.

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So now we have five cars in our fleet.

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And I want to go back execute again and when we look in the list the expectation is that we're going

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to see the Subaru that was just added.

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So that's a zero first step towards connecting to your database.

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So let's just review what we did.

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We set up our farm load events because we realized that there's certain data coming from the database

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that needs to be presented or our farm.

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By the time the farm loads.

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So after initializing a connection to the database through the use of my object our reference to the

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entities models.

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So we have our entity model.

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I initialize an object of the type of that entity model.

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All right.

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So I declared it's up here initialize it here and then I realized that I needed data from that database

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before the form loaded.

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So I set up a farm load event which queried the table and basically just did the initial steps toward

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setting up the combo box so these steps are pretty much universal.

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This is not you.

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This is not unique to the fact that I'm using the entity model and this and that.

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This is how you set up a combo box to inherit from my list of items whether it's a static list or a

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list going from the database where they're using link or you're using the other methods that are there.

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The fact is that this is all you data by and are you buying the objects to your controller or to your

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combo box rather.

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All right.

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So once again we run our query got to stuff cars from our database.

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Literally if you read from right to left that's left that's all it is saying give me a list of the types

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of cars from the database and store it in this variable and then later on we say that we want to display

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the name and store the idea and then the data source should be from the list of the cars that we just

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retrieved from the database.

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And so in our form loads we see that it is running that query and getting all that data if you want

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to put our breakpoint here and restart application and just go step by step to see exactly what happens

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just to be sure.

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Then you can feel free to do so but that is our first step to connecting to the database.

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In the next video we will be looking at how when we click submit no all we do when we click submit is

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you know display the information.

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Next time we want to actually save it in our car or into the record table.

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So that's all we'd be doing in the next video.