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In my blog, I delve into the world of programming web technologies, Linux, Unix-like, and graphic design using free tools on Linux.

Saturday, July 13, 2024

CodeIgniter - migration

"Migration" is the name for the process in which we load the migration file via the CLI command and, based on the loaded settings, create tables/columns in the database. The point is that when we transfer the project to another computer, we can create the entire database skeleton with a CLI command.

Let's prepare the project

If I don't want to write about how to prepare the project, you can find everything here. To create a migration file:

php spark make:migration main

With this we get the file:

./app/Database/Migrations/2022-08-07-084359_Main.php

With content:

namespace App\Database\Migrations;
use CodeIgniter\Database\Migration;
class Main extends Migration
{
 public function up()
 {
 //
 }
 public function down()
 {
 //
 }
}
With the "up" method we enter data into the database, and with the "down" method we delete the entered data. The "up" method with the entered data looks like this:

public function up()
{
 $this->forge->addField([
 'id' => [
 'type' => 'INT',
 'constraint' => 5,
 'unsigned' => true,
 'auto_increment' => true,
 ],
 'name' => [
 'type' => 'VARCHAR',
 'constraint' => '256',
 'null' => false
 ],
 'updated_at' => [
 'type' => 'datetime',
 'null' => true,
 ],
 'created_at datetime default current_timestamp',
 ]);
 $this->forge->addPrimaryKey('id');
 $this->forge->createTable('products');
}

After entering the data in the "up" method in the terminal, we run:

php spark migrate

...and now we see that the table and columns are in the database:

Rollback

This command executes what is in the "down" method of the migration file. Here we specify that we will delete the "products" table:

public function down()
{
 $this->forge->dropTable('products');
}
The CLI command looks like this:

php spark migrate:rollback
Multiple tables in one migration
If we want to have more tables in one migration file, we simply add them one below the other in the "up" and "down" methods.

public function up()
{
 $this->forge->addField([
 ...
 $this->forge->createTable('products');

 $this->forge->addField([
 ...
 $this->forge->createTable('users');
}
public function down()
{
 $this->forge->dropTable('products');
 $this->forge->dropTable('users');
}

Foreign keys

For example, we want the "userId" column to be connected to the "id" column in the "users" table.

$this->forge->addField([
...
 'userId' => [
 'type' => 'INT',
 'unsigned' => true,
 'null' => false,
 ],
...
]);
...
$this->forge->addForeignKey('userId', 'users', 'id', 'CASCADE', 'CASCADE');

That's it!

posted by damirs @ July 13, 2024