01 - init and config

The first step in performing a migration is to create the necessary files and folders. sequelize init does this process for us.

Running Sequelize init

1. Open a terminal window and navigate to your server folder.

2. In the terminal window, run sequelize init. This will create the following folders: config, models, migrations, and seeders. The table below goes into more detail on the purpose of each folder.

   NOTE: We already have a models folder, so that part is skipped.

3. Look at your project in VS Code. You should see all of the new folders.

Folder	Purpose
config	The configuration settings for your database migrations.
migrations	The actual migration files. More on this later.
models	The files used to create your tables.
seeders	Files that can add data to your database. More on this later.

config.js

Inside the config folder, open config.json. We need to make a few changes to give Sequelize the ability to access our database. Currently, the file looks like this:

{
  "development": {
    "username": "root",
    "password": null,
    "database": "database_development",
    "host": "127.0.0.1",
    "dialect": "mysql"
  },
  "test": {
    "username": "root",
    "password": null,
    "database": "database_test",
    "host": "127.0.0.1",
    "dialect": "mysql"
  },
  "production": {
    "username": "root",
    "password": null,
    "database": "database_production",
    "host": "127.0.0.1",
    "dialect": "mysql"
  }
}

You can see that nothing here points to our database right now. Additionally, there are several different environments available: development, test, and production. For our purposes, it doesn't matter which environment is used, but there are times when it will. For now, we'll just change everything to what we need. Delete the information in config.js and add the following:

{
  "development": {
    "username": "postgres", //1
    "password": "YOUR-POSTGRES-PASSWORD-HERE",  //2
    "database": "workoutlog", //3
    "host": "127.0.0.1",
    "port": "5432", //4
    "dialect": "postgres" //5
  },
  "test": {
    "username": "postgres",
    "password": "YOUR-POSTGRES-PASSWORD-HERE",
    "database": "workoutlog",
    "host": "127.0.0.1",
    "port": "5432",
    "dialect": "postgres"
  },
  "production": {
    "username": "postgres",
    "password": "YOUR-POSTGRES-PASSWORD-HERE",
    "database": "workoutlog",
    "host": "127.0.0.1",
    "port": "5432",
    "dialect": "postgres"
  }
}

Here's what changed:

1. The local postgres username to postgres

2. Your postgres password.

3. The name of your database.

4. We have to add the port property so that Sequelize can talk to the database on the right port.

5. Sequelize can interact with several different versions of SQL databases, each with a slightly different syntax for SQL queries. This tells Sequelize what we are currently using.