Using Database in a Laravel Application

How Laravel connect to your Database

Configurations

Item in `.env`	Configuration File	Description
`DB_CONNECTION`	`config/database.php`	Which database software to use (driver)
`DB_DATABASE`	`config/database.php`	Name of the database to use
`DB_PASSWORD`	`config/database.php`	Password for database connection
`DB_USERNAME`	`config/database.php`	Username for database connection
`DB_PORT`	`config/database.php`	Port for database connection
`DB_HOST`	`config/database.php`	Host IP for database connection

Migrations

Database: Migrations - Laravel 12.x - The PHP Framework For Web Artisans

A migration makes structural changes to the database

<aside> 💡

Migration commands

Applying migrations
```
php artisan migrate
```
Creating a new migration
```
php artisan make:migration
```
Rolling back the last ran migration
```
php artisan migrate:rollback
```

</aside>

Each migration is a class extending Migration class
- Each migration class has a up and down method:
  - up makes the changes to database according to the migration
  - down rolls back changes to database made by the migration
Migrations are in database/migrations folder

<aside> 💡

Conventions for naming migrations:

Creation of a table:

create_[table-name]_table
Adding a column to an existing table:

add_[column-name]_column_to_[table-name]_table
Renaming an existing column in an existing table:

rename_[column-name]_column_in_[table-name]_table

</aside>

Example for Table Creation Migration

php artisan make:migration create_books_table

<?php

use Illuminate\\Database\\Migrations\\Migration;
use Illuminate\\Database\\Schema\\Blueprint;
use Illuminate\\Support\\Facades\\Schema;

return new class extends Migration
{
    public function up(): void
    {
        Schema::create('books', function (Blueprint $table) {
            $table->id();
            $table->string("name");
            $table->timestamps();
        });
    }

    public function down(): void
    {
        Schema::dropIfExists('books');
    }
};

Example for Adding a Column to an Existing Table Migration

php artisan make:migration add_publication_year_column_to_books_table

<?php

use Illuminate\\Database\\Migrations\\Migration;
use Illuminate\\Database\\Schema\\Blueprint;
use Illuminate\\Support\\Facades\\Schema;

return new class extends Migration
{
    public function up(): void
    {
        Schema::table('books', function (Blueprint $table) {
            $table->string('publication_year')->after("id")->nullable();
        });
    }

    public function down(): void
    {
        Schema::table('books', function (Blueprint $table) {
            $table->dropColumn('publication_year');
        });
    }
};

Example for Renaming an Existing Column in an Existing Table

php artisan make:migration rename_name_column_in_books_table

<?php

use Illuminate\\Database\\Migrations\\Migration;
use Illuminate\\Database\\Schema\\Blueprint;
use Illuminate\\Support\\Facades\\Schema;

return new class extends Migration
{
    public function up(): void
    {
        Schema::table('books', function (Blueprint $table) {
            $table->renameColumn('name', 'title');
        });
    }

    public function down(): void
    {
        Schema::table('books', function (Blueprint $table) {
            $table->renameColumn('title', 'name');
        });
    }
};