Step 2: Use the Built-in DB

Populate the built-in DataBase

Now, let’s make our HelloWorld web app more interesting by accessing data from the built-in DB.

What about saying “Hello !” to your favorite superheros ? Let’s populate the database with them.

Step 1: Add a javascript Back-End project to your solution

First we need to add a back-end project. It will contain the data, datamodel and the business code.

  • Right-click on the name of your solution. (New>Project) (or command+shift+N).
  • Name your solution “back-end-superheroes”
  • Select “Back-end” and “Wakanda Javascript”
  • Click on create

Step 2: Edit you data model Visually

First, we’re going to create our datamodel.

To manage your data easily and quickly, Wakanda provides a Visual Data Editor.

It allows you to create your classes, and their properties visually.

1 - Create a Superhero and a Moviedataclasses.

Give them respectively the attribute name and title of type string and save.

TIPS:

  • The attribute ID is given by default to all dataclasses created. The classes instantiation are named “Entity” in Wakanda.
  • They are similar to classical js class instanciation, except a new ID is automatically created at each generation in order to keep entities uniqueness in the datastore.

2 - Add an attribute movie to Superherodataclass and give it the type Movie. The relationship between the two classes is automatically displayed in the model

The JSON file of your datamodel is automatically updated each time you save.

TIPS:

  • You can click on “source” button to see the JSON file generated
  • ds is the object representing the whole datamodel, corresponding to this JSON file.
  • Two objects constructors have been generated : Superhero and Movie.

Step 2 : Generate data

Now, we are going to write a small javascript script to generate data:

  • Create a folder script at the root of back-end-superheroes (Right click on the folder and New >Folder)
  • Add a js file addSuperheroes.js in it (Right click on the folder or File > New >JS File).

  • Use the generated constructor Superhero to add your top 3 Superhero in the the built-in database.
ds.Superhero.remove(); //clean the database from all former Superhero generated
new ds.Superhero({name:"Batman"}).save();
new ds.Superhero({name:"Wolverine"}).save();
var favoriteSupehero = new ds.Superhero({name:"Wonder Woman"});
favoriteSupehero.save();
ds.Superhero.all();
  • click on the “Play” icon.

Your three favorite superheroes are now saved in the datastore !

TIPS:

  • The constructors generated by the visual editor always take an object as argument (not the attributes values unlike a classical JS object constructor).
  • save() is a Wakanda method used to save the JSON corresponding to the Entity (meaning only its attributes) in the datastore.

WARNING:

  • The JSON saved are not related to the var favoriteSuperhero in the datastore, nor in your front-end calls.
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