Migration in Laravel

Tuesday, 22/11/2022

Tram Ho

1. Migration.

Migration can be understood as a version of your database at a point in time.
It makes it easier to share your database schema when working as a team.
Just run the migration and you can generate a schema just like you defined.
And of course you can also edit the columns in the database.

2 Create migrations.

To create a migration in laravel you just need to run the following command in terminal:

php artisan make:migration ten_migration --create=table_name
//hoặc
php artisan make:migration ten_migration --table=table_name

php artisan make:migration ten_migration --create=table_name

//hoặc

php artisan make:migration ten_migration --table=table_name

The result after running the command is that you get a migration file in the database/migrations directory
The --create or --table part is to indicate the name of the table and whether the migration will create a new table.
Each migration file is named including timestamp + tên to identify the order of migartion with each other.

3 Migration files.

<span class="token php language-php"><span class="token delimiter important">&lt;?php</span>

<span class="token keyword">use</span> <span class="token package">Illuminate  Database  Migrations  Migration</span> <span class="token punctuation">;</span>
<span class="token keyword">use</span> <span class="token package">Illuminate  Database  Schema  Blueprint</span> <span class="token punctuation">;</span>
<span class="token keyword">use</span> <span class="token package">Illuminate  Support  Facades  Schema</span> <span class="token punctuation">;</span>

<span class="token keyword">return</span> <span class="token keyword">new</span> <span class="token keyword">class</span> <span class="token class-name-definition class-name">extends</span> <span class="token class-name">Migration</span>
<span class="token punctuation">{</span>
    <span class="token comment">/**
     * Run the migrations.
     *
     * @return void
     */</span>
    <span class="token keyword">public</span> <span class="token keyword">function</span> <span class="token function-definition function">up</span> <span class="token punctuation">(</span> <span class="token punctuation">)</span>
    <span class="token punctuation">{</span>
        <span class="token class-name static-context">Schema</span> <span class="token operator">::</span> <span class="token function">create</span> <span class="token punctuation">(</span> <span class="token string single-quoted-string">'users'</span> <span class="token punctuation">,</span> <span class="token keyword">function</span> <span class="token punctuation">(</span> <span class="token class-name type-declaration">Blueprint</span> <span class="token variable">$table</span> <span class="token punctuation">)</span> <span class="token punctuation">{</span>
            <span class="token variable">$table</span> <span class="token operator">-&gt;</span> <span class="token function">id</span> <span class="token punctuation">(</span> <span class="token punctuation">)</span> <span class="token punctuation">;</span>
            <span class="token variable">$table</span> <span class="token operator">-&gt;</span> <span class="token keyword type-declaration">string</span> <span class="token punctuation">(</span> <span class="token string single-quoted-string">'email'</span> <span class="token punctuation">)</span> <span class="token operator">-&gt;</span> <span class="token function">unique</span> <span class="token punctuation">(</span> <span class="token punctuation">)</span> <span class="token punctuation">;</span>
            <span class="token variable">$table</span> <span class="token operator">-&gt;</span> <span class="token function">timestamp</span> <span class="token punctuation">(</span> <span class="token string single-quoted-string">'email_verified_at'</span> <span class="token punctuation">)</span> <span class="token operator">-&gt;</span> <span class="token function">nullable</span> <span class="token punctuation">(</span> <span class="token punctuation">)</span> <span class="token punctuation">;</span>
            <span class="token variable">$table</span> <span class="token operator">-&gt;</span> <span class="token keyword type-declaration">string</span> <span class="token punctuation">(</span> <span class="token string single-quoted-string">'password'</span> <span class="token punctuation">)</span> <span class="token punctuation">;</span>
            <span class="token variable">$table</span> <span class="token operator">-&gt;</span> <span class="token function">rememberToken</span> <span class="token punctuation">(</span> <span class="token punctuation">)</span> <span class="token punctuation">;</span>
            <span class="token variable">$table</span> <span class="token operator">-&gt;</span> <span class="token function">timestamps</span> <span class="token punctuation">(</span> <span class="token punctuation">)</span> <span class="token punctuation">;</span>
        <span class="token punctuation">}</span> <span class="token punctuation">)</span> <span class="token punctuation">;</span>
    <span class="token punctuation">}</span>

    <span class="token comment">/**
     * Reverse the migrations.
     *
     * @return void
     */</span>
    <span class="token keyword">public</span> <span class="token keyword">function</span> <span class="token function-definition function">down</span> <span class="token punctuation">(</span> <span class="token punctuation">)</span>
    <span class="token punctuation">{</span>
        <span class="token class-name static-context">Schema</span> <span class="token operator">::</span> <span class="token function">dropIfExists</span> <span class="token punctuation">(</span> <span class="token string single-quoted-string">'users'</span> <span class="token punctuation">)</span> <span class="token punctuation">;</span>
    <span class="token punctuation">}</span>
<span class="token punctuation">}</span> <span class="token punctuation">;</span>
</span>

<?php

use Illuminate Database Migrations Migration ;

use Illuminate Database Schema Blueprint ;

use Illuminate Support Facades Schema ;

return new class extends Migration

{

/**

* Run the migrations.

* @return void

*/

public function up ( )

{

Schema :: create ( 'users' , function ( Blueprint $table ) {

$table -> id ( ) ;

$table -> string ( 'email' ) -> unique ( ) ;

$table -> timestamp ( 'email_verified_at' ) -> nullable ( ) ;

$table -> rememberToken ( ) ;

$table -> timestamps ( ) ;

} ) ;

}

/**

* Reverse the migrations.

* @return void

*/

public function down ( )

{

Schema :: dropIfExists ( 'users' ) ;

}

} ;

In this file there are 2 functions, up and down .
Basically, function up will run when you execute php artisan migrate command and function down will run when you execute php artisan migrate:rollback command.
Of course, when function up is executed, it will create a table uers in your database and function down will delete that table.

4 Run migration

As I mentioned above, to execute the migration files, you just need to run the command:

php artisan migrate

1 2	php artisan migrate

And to go back to the previous state, run the command:

php artisan migrate:rollback

1 2	php artisan migrate:rollback

You can also specify the number of recovery steps with the --step option.

php artisan migrate:rollback --step=5

1 2	php artisan migrate:rollback --step=5

Laravel also gives you a way so that you don’t have to re-run migrate every time that rollback is

php artisan migrate:reset

1 2	php artisan migrate:reset

5. Schema

You can understand Schema is used to tạo, sửa, xóa,.. things related to tables in the database.

<span class="token comment">//tạo bảng</span>
<span class="token class-name static-context">Schema</span> <span class="token operator">::</span> <span class="token function">create</span> <span class="token punctuation">(</span> <span class="token string single-quoted-string">'users'</span> <span class="token punctuation">,</span> <span class="token keyword">function</span> <span class="token punctuation">(</span> <span class="token class-name type-declaration">Blueprint</span> <span class="token variable">$table</span> <span class="token punctuation">)</span> <span class="token punctuation">{</span> <span class="token punctuation">}</span>
<span class="token comment">//đổi tên bảng</span>
<span class="token class-name static-context">Schema</span> <span class="token operator">::</span> <span class="token function">rename</span> <span class="token punctuation">(</span> <span class="token string single-quoted-string">'post'</span> <span class="token punctuation">,</span> <span class="token string single-quoted-string">'posts'</span> <span class="token punctuation">)</span>
<span class="token comment">//xóa bảng</span>
<span class="token class-name static-context">Schema</span> <span class="token operator">::</span> <span class="token function">drop</span> <span class="token punctuation">(</span> <span class="token string single-quoted-string">'users'</span> <span class="token punctuation">)</span> <span class="token punctuation">;</span>
<span class="token class-name static-context">Schema</span> <span class="token operator">::</span> <span class="token function">dropIfExists</span> <span class="token punctuation">(</span> <span class="token string single-quoted-string">'users'</span> <span class="token punctuation">)</span> <span class="token punctuation">;</span>

//tạo bảng

//đổi tên bảng

Schema :: rename ( 'post' , 'posts' )

//xóa bảng

Schema :: drop ( 'users' ) ;

You can also check if the table or column exists by

<span class="token comment">// kiểm tra bảng tồn tại</span>
<span class="token keyword">if</span> <span class="token punctuation">(</span> <span class="token class-name static-context">Schema</span> <span class="token operator">::</span> <span class="token function">hasTable</span> <span class="token punctuation">(</span> <span class="token string single-quoted-string">'users'</span> <span class="token punctuation">)</span> <span class="token punctuation">)</span> <span class="token punctuation">{</span>
    <span class="token comment">//</span>
<span class="token punctuation">}</span>
<span class="token comment">// kiểm tra cột tồn tại</span>
<span class="token keyword">if</span> <span class="token punctuation">(</span> <span class="token class-name static-context">Schema</span> <span class="token operator">::</span> <span class="token function">hasColumn</span> <span class="token punctuation">(</span> <span class="token string single-quoted-string">'users'</span> <span class="token punctuation">,</span> <span class="token string single-quoted-string">'email'</span> <span class="token punctuation">)</span> <span class="token punctuation">)</span> <span class="token punctuation">{</span>
    <span class="token comment">//</span>
<span class="token punctuation">}</span>

// kiểm tra bảng tồn tại

if ( Schema :: hasTable ( 'users' ) ) {

//

}

// kiểm tra cột tồn tại

if ( Schema :: hasColumn ( 'users' , 'email' ) ) {

//

}

Create column:

<span class="token class-name static-context">Schema</span> <span class="token operator">::</span> <span class="token function">create</span> <span class="token punctuation">(</span> <span class="token string single-quoted-string">'users'</span> <span class="token punctuation">,</span> <span class="token keyword">function</span> <span class="token punctuation">(</span> <span class="token class-name type-declaration">Blueprint</span> <span class="token variable">$table</span> <span class="token punctuation">)</span> <span class="token punctuation">{</span>
    <span class="token variable">$table</span> <span class="token operator">-&gt;</span> <span class="token function">type</span> <span class="token punctuation">(</span> <span class="token string single-quoted-string">'ten_cot'</span> <span class="token punctuation">)</span> <span class="token punctuation">;</span>   <span class="token comment">//type ở đây là chỉ các kiểu mà cột đó cần</span>
    <span class="token variable">$table</span> <span class="token operator">-&gt;</span> <span class="token function">type</span> <span class="token punctuation">(</span> <span class="token string single-quoted-string">'ten_cot'</span> <span class="token punctuation">)</span> <span class="token punctuation">;</span>
<span class="token punctuation">}</span>

$table -> type ( 'ten_cot' ) ; //type ở đây là chỉ các kiểu mà cột đó cần

}

You can refer to the data types here: here

6. Foreign Key Constraints

To create constraints for tables, we can use the following syntax to bind for 2 tables:

<span class="token class-name static-context">Schema</span> <span class="token operator">::</span> <span class="token function">table</span> <span class="token punctuation">(</span> <span class="token string single-quoted-string">'posts'</span> <span class="token punctuation">,</span> <span class="token keyword">function</span> <span class="token punctuation">(</span> <span class="token variable">$table</span> <span class="token punctuation">)</span> <span class="token punctuation">{</span>
    <span class="token variable">$table</span> <span class="token operator">-&gt;</span> <span class="token function">integer</span> <span class="token punctuation">(</span> <span class="token string single-quoted-string">'user_id'</span> <span class="token punctuation">)</span> <span class="token operator">-&gt;</span> <span class="token function">unsigned</span> <span class="token punctuation">(</span> <span class="token punctuation">)</span> <span class="token punctuation">;</span>

    <span class="token variable">$table</span> <span class="token operator">-&gt;</span> <span class="token function">foreign</span> <span class="token punctuation">(</span> <span class="token string single-quoted-string">'user_id'</span> <span class="token punctuation">)</span> <span class="token operator">-&gt;</span> <span class="token function">references</span> <span class="token punctuation">(</span> <span class="token string single-quoted-string">'id'</span> <span class="token punctuation">)</span> <span class="token operator">-&gt;</span> <span class="token function">on</span> <span class="token punctuation">(</span> <span class="token string single-quoted-string">'users'</span> <span class="token punctuation">)</span> <span class="token punctuation">;</span>
<span class="token punctuation">}</span> <span class="token punctuation">)</span> <span class="token punctuation">;</span>

Schema :: table ( 'posts' , function ( $table ) {

$table -> integer ( 'user_id' ) -> unsigned ( ) ;

$table -> foreign ( 'user_id' ) -> references ( 'id' ) -> on ( 'users' ) ;

} ) ;

Conclusion

Above are the basics of migration I would like to introduce to you. Hope it will help you.
The following section will introduce you to models in Laravel.

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Source : Viblo

Migration in Laravel

1. Migration.

2 Create migrations.

3 Migration files.

4 Run migration

5. Schema

6. Foreign Key Constraints

Conclusion

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