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The Database Forge class in CodeIgniter 4 provides a powerful collection of tools for working with database structures and schema alterations. The Database Forge class allows you to conduct a wide range of database operations within the CodeIgniter framework, such as creating tables, updating columns, adding indexes, and much more.

In this in-depth lesson, we will look at the Database Forge class in CodeIgniter 4. We will walk you through the step-by-step method of using this class to easily construct and alter database structures.

The Database Forge class will be your go-to tool whether you need to create a new database from start or make changes to an existing schema.

Let’s get started.

CodeIgniter 4 Installation

To create a CodeIgniter 4 setup run this given command into your shell or terminal. Please make sure composer should be installed.

composer create-project codeigniter4/appstarter codeigniter-4

Assuming you have successfully installed application into your local system.

What is Database Forge Class?

The Database Forge class in CodeIgniter 4 provides a strong set of tools for modifying database structures and schema.

It contains methods that help you manage your database.

Load the Forge Class as follows:

$forge = \Config\Database::forge();

If the database you wish to manage is not the default one, you may alternatively supply another database group name to the DB Forge loader:

$this->forge = \Config\Database::forge('other_db');

How To Create Database Using Forge Object

We can use createDatabase() method of database forge to create database.

Here, is the call to create it:

$forge->createDatabase('myDb')

It returns true/false based on success or failure.

If the optional second parameter is set to true, an IF EXISTS statement will be added or a database will be checked for existence before being created (depending on the DBMS).

$forge->createDatabase('myDb', true);

How To Drop Database Using Forge Object

To drop a schema, you can use dropDatabase() method of it.

Here, is the way to call it.

$forge->dropDatabase('myDb');

It also returns true/false based on success or failure.

How To Create Table Using Forge Object

When building tables, you may want to do a few things. Change the columns, add fields, and add keys to the table. CodeIgniter has a way for doing this.

We will use these following methods to create a table with defined fields and also with keys.

$forge->addField();

$forge->addPrimaryKey();

$forge->addUniqueKey();

$forge->createTable();

Here, is the complete code by which you can create a table structure in database.

<?php

namespace App\Database\Migrations;

use CodeIgniter\Database\Migration;

class CreatePostsTable extends Migration
{
    public function up()
    {
        $this->forge->addField([
            "id" => [
                "type" => "INT",
                "constraint" => 5,
                "auto_increment" => true,
                "unsigned" => true,
            ],
            "title" => [
                "type" => "VARCHAR",
                "constraint" => 80,
                "null" => false,
            ],
            "content" => [
                "type" => "TEXT",
                "null" => true,
            ],
            "created_at datetime default current_timestamp",
            "updated_at datetime default current_timestamp",
        ]);

        $this->forge->addPrimaryKey("id");
        $this->forge->createTable("posts");
    }

    public function down()
    {
        $this->forge->dropTable("posts");
    }
}

That’s it.

We hope this article helped you to learn about About Database Forge Class of CodeIgniter 4 Tutorial in a very detailed way.

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