Migration creation in Laravel - Mini Project: Build & Apply

Migration creation

📖 Scenario: You are building a simple Laravel application to manage a list of books in a library. You need to create a database table to store book information.

🎯 Goal: Create a Laravel migration file that defines a books table with specific columns.

📋 What You'll Learn

Create a migration file named create_books_table

Define a books table with columns: id, title, author, published_year, and timestamps

Set id as an auto-incrementing primary key

Make title and author columns strings

Make published_year an integer

💡 Why This Matters

🌍 Real World

Migrations help you create and modify database tables in a safe, version-controlled way when building Laravel applications.

💼 Career

Knowing how to write migrations is essential for backend Laravel developers to manage database schema changes collaboratively.

1

Create the migration class skeleton

Create a migration class named CreateBooksTable that extends Migration. Inside it, add empty up and down methods.

Laravel

<?php

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

class CreateBooksTable extends Migration
{
    public function up()
    {
        // Your code here
    }

    public function down()
    {
        // Your code here
    }
}

Hint

Start by defining the migration class and the two required methods up and down.

2

Add the table creation schema

Inside the up method, use Schema::create to create a table named books with a Blueprint callback parameter named $table.

Laravel

<?php

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

class CreateBooksTable extends Migration
{
    public function up()
    {
        Schema::create('books', function (Blueprint $table) {
            // Your code here
        });
    }

    public function down()
    {
    }
}

Hint

Use Schema::create with the table name books and a callback function with $table as parameter.

3

Define the columns inside the table

Inside the Schema::create callback, add these columns to $table: an auto-incrementing id, string title, string author, integer published_year, and timestamps.

Laravel

<?php

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

class CreateBooksTable extends Migration
{
    public function up()
    {
        Schema::create('books', function (Blueprint $table) {
            // Add columns here
        });
    }

    public function down()
    {
    }
}

Hint

Use the Laravel schema builder methods to add the columns with the exact names and types.

4

Add the table drop in the down method

Inside the down method, add code to drop the books table using Schema::dropIfExists('books').

Laravel

id();
            $table->string('title');
            $table->string('author');
            $table->integer('published_year');
            $table->timestamps();
        });
    }

    public function down()
    {
        // Your code here
    }
}

Hint

Use Schema::dropIfExists with the table name books to remove the table when rolling back.

Practice

1. What is the primary purpose of a migration in Laravel?

easy

A. To create and modify database tables in a structured way

B. To handle user authentication

C. To manage routes in the application

D. To compile CSS and JavaScript assets

Solution

1. Step 1: Understand migration role

   Migrations are designed to manage database schema changes safely and consistently.

2. Step 2: Compare with other options

   Options A, C, and D relate to authentication, routing, and asset compilation, which are not migration tasks.

3. Final Answer:

   To create and modify database tables in a structured way -> Option A

4. Quick Check:

   Migration = Manage database tables [OK]

Hint: Migrations always deal with database tables [OK]

Common Mistakes:

• Confusing migrations with routing or authentication
• Thinking migrations compile assets
• Assuming migrations handle user sessions

2. Which command correctly creates a new migration file in Laravel?

easy

A. php artisan migration:create users

B. php artisan make:migration create_users_table

C. php artisan new:migration users_table

D. php artisan create:migration users

Solution

1. Step 1: Recall Laravel migration command

   The correct command to create a migration is php artisan make:migration followed by the migration name.

2. Step 2: Check each option

   Only php artisan make:migration create_users_table uses the correct syntax and command name.

3. Final Answer:

   php artisan make:migration create_users_table -> Option B

4. Quick Check:

   Use 'make:migration' to create migrations [OK]

Hint: Use 'make:migration' command to create migrations [OK]

Common Mistakes:

• Using wrong artisan command names
• Omitting 'make:' prefix
• Confusing migration creation with other artisan commands

3. Given this migration snippet, what will happen when running php artisan migrate?

public function up()
{
    Schema::create('posts', function (Blueprint $table) {
        $table->id();
        $table->string('title');
        $table->text('content');
        $table->timestamps();
    });
}

medium

A. Updates the 'posts' table by adding new columns

B. Deletes the 'posts' table if it exists

C. Creates a 'posts' table with id, title, content, and timestamps columns

D. Throws an error because 'timestamps' is not a valid method

Solution

1. Step 1: Analyze the up() method

   The code uses Schema::create to make a new table named 'posts' with columns: id, title, content, and timestamps.

2. Step 2: Understand Laravel Schema methods

   $table->timestamps() adds created_at and updated_at columns automatically. This is valid and common.

3. Final Answer:

   Creates a 'posts' table with id, title, content, and timestamps columns -> Option C

4. Quick Check:

   Schema::create + columns = new table [OK]

Hint: Schema::create builds new tables with specified columns [OK]

Common Mistakes:

• Thinking timestamps() is invalid
• Confusing create with update
• Assuming it deletes tables

4. Identify the error in this migration code:

public function up()
{
    Schema::create('comments', function (Blueprint $table) {
        $table->increments('id');
        $table->string('text');
        $table->timestamps;
    });
}

medium

A. String column 'text' must have a length specified

B. Using increments instead of id method

C. Table name should be singular, not plural

D. Missing parentheses after timestamps method call

Solution

1. Step 1: Check method calls in migration

   $table->timestamps is missing parentheses. It should be $table->timestamps() to call the method.

2. Step 2: Validate other parts

   Using increments('id') is valid, plural table names are allowed, and string columns default length is 255 if not specified.

3. Final Answer:

   Missing parentheses after timestamps method call -> Option D

4. Quick Check:

   Method calls need parentheses () [OK]

Hint: Always add () when calling migration methods [OK]

Common Mistakes:

• Forgetting parentheses on method calls
• Thinking increments is invalid
• Believing table names must be singular

5. You want to create a migration that adds a nullable 'bio' text column to the existing 'users' table. Which up() method code is correct?

hard

A. Schema::table('users', function (Blueprint $table) {
$table->text('bio')->nullable();
});

B. Schema::create('users', function (Blueprint $table) {
$table->text('bio')->nullable();
});

C. Schema::modify('users', function (Blueprint $table) {
$table->text('bio')->nullable();
});

D. Schema::addColumn('users', 'bio', 'text')->nullable();

Solution

1. Step 1: Understand how to modify existing tables

   To add a column to an existing table, use Schema::table with a closure defining the new column.

2. Step 2: Evaluate each option

   Schema::table('users', function (Blueprint $table) { $table->text('bio')->nullable(); }); correctly uses Schema::table and adds a nullable text column. Schema::create('users', function (Blueprint $table) { $table->text('bio')->nullable(); }); tries to create a new table, which is wrong. Options A and D use invalid Schema methods.

3. Final Answer:

   Schema::table('users', function (Blueprint $table) { $table->text('bio')->nullable(); }); -> Option A

4. Quick Check:

   Use Schema::table to add columns [OK]

Hint: Use Schema::table to change existing tables [OK]

Common Mistakes:

• Using Schema::create instead of Schema::table
• Using non-existent Schema methods
• Forgetting nullable() for optional columns