Schema, the organization of fields and records, is one of the first considerations to make when creating or interacting with an existing database.

Lucid Chart

The interactions between each piece of any application is decided by the developer.

$ sudo service mysql start
$ sudo service mysql status
$ mysql -u root -p

mysql>

This code will start up your database which is required in order to start the server in the next step.

In this sprint we define a schema.sql file that can be executed as a script and passed into mysql in a bash terminal to create our database and tables. If the database we are trying to create already exists, we'll have to drop it from mysql first.

mysql> drop database chat;

Then we are ready to rebuild the database.

$ mysql -u root < server/schema.sql

Back in mysql we can confirm this worked.

mysql> show databases;
+--------------------+
| Database           |
+--------------------+
| chat               |
| information_schema |
| mysql              |
| performance_schema |
| sys                |
+--------------------+

mysql> use chat
mysql> show tables;
+----------------+
| Tables_in_chat |
+----------------+
| messages       |
| users          |
+----------------+

mysql> describe users;
+----------+-------------+------+-----+---------+----------------+
| Field    | Type        | Null | Key | Default | Extra          |
+----------+-------------+------+-----+---------+----------------+
| id       | int         | NO   | PRI | NULL    | auto_increment |
| username | varchar(40) | NO   |     | NULL    |                |
+----------+-------------+------+-----+---------+----------------+

It's always a good idea to inspect the package.json file to look for dependencies and scripts. In this case we see that we can start our server using the below script.

  "scripts": {
    "start": "node ./server/app.js",
    /* ... */
  },

$ npm start

Now that the server and database are fired up, you're ready to send HTTP requests! The simplest way to do this is via postman.

Look for messages in the server terminal, thanks to the morgan package that express uses in app.js. This is all assuming that the routes are configured correctly, requests have to be handled at their endpoints!

A couple great methods for responding to requests include

• res.sendStatus(201);
  • successfully created
• res.json(data);
  • respond with automatic headers

Be more specific than the generic success/failure status codes.

• 201 resource created
• 404 not found

The libraries we are importing are managed by npm. Therefore the docs we should be ready are npm docs. MySQL is a database language that can be interacted with by virtually any programming language! We have to read about the implementation we're using!