Laravel 5 framework learning database migration (Migrations), laravelmigrations_PHP tutorial

Laravel 5 framework learning database migrations (Migrations), laravelmigrations

database migrations is one of the most powerful features of laravel. Database migration can be understood as a version controller for the database.

Contains two migration files in the database/migrations directory, one to create the user table and one for user password reset.

In the migration file, the up method is used to create the data table, and the down method is used to roll back, that is, delete the data table.

Perform database migration

Copy code The code is as follows:
php artisan migrate
#output
Migration table created successfully.
Migrated: 2014_10_12_000000_create_users_table
Migrated: 2014_10_12_100000_create_password_resets_table

Looking at the mysql database, you can see that three tables have been generated. The migratoins table is the migration record table, users and pasword_resets.

If there is a problem with the design, perform a database rollback

Copy code The code is as follows:
php artisan migrate:rollback
#output
Rolled back: 2014_10_12_100000_create_password_resets_table
Rolled back: 2014_10_12_000000_create_users_table

Looking at the mysql database again, only the migrations table is left, and users password_resets has been deleted.

Modify the migration file and perform the migration again.

New migration

Copy code The code is as follows:
php artisan make:migration create_article_table --create='articles'
#output
Created Migration: 2015_03_28_050138_create_article_table

New files are generated under database/migrations.

<&#63;php

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

class CreateArticleTable extends Migration {

 /**
 * Run the migrations.
 *
 * @return void
 */
 public function up()
 {
 Schema::create('articles', function(Blueprint $table)
 {
  $table->increments('id');
  $table->timestamps();
 });
 }

 /**
 * Reverse the migrations.
 *
 * @return void
 */
 public function down()
 {
 Schema::drop('articles');
 }

}

The id column is automatically added and grows automatically. timestamps() will automatically generate two time columns: created_at and updated_at. Let’s add some fields:

 public function up()
 {
 Schema::create('articles', function(Blueprint $table)
 {
  $table->increments('id');
      $table->string('title');
      $table->text('body');
      $table->timestamp('published_at');
  $table->timestamps();
 });
 }

Execute migration:

Copy code The code is as follows:
php artisan migrate

New datasheet now available.

Suppose we need to add a new field, you can roll back, then modify the migration file, and perform the migration again, or you can directly create a new migration file

Copy code The code is as follows:
php artisan make:migration add_excerpt_to_articels_table

View the newly generated migration file

<&#63;php

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

class AddExcerptToArticelsTable extends Migration {

 /**
 * Run the migrations.
 *
 * @return void
 */
 public function up()
 {
 //
 }

 /**
 * Reverse the migrations.
 *
 * @return void
 */
 public function down()
 {
 //
 }

}

Only empty up and down methods. We can add the code manually, or we let Laravel generate the basic code for us. Delete this file and regenerate the migration file. Pay attention to adding parameters:

Copy code The code is as follows:
php artisan make:migration add_excerpt_to_articels_table --table='articles'

Now, there is initial code in the up method.

 public function up()
 {
 Schema::table('articles', function(Blueprint $table)
 {
  //
 });
 }

Add actual data modification code:

 public function up()
 {
 Schema::table('articles', function(Blueprint $table)
 {
  $table->text('excerpt')->nullable();
 });
 }
 
 public function down()
 {
 Schema::table('articles', function(Blueprint $table)
 {
  $table->dropColumn('excerpt');
 });
 }

nullable() means that the field can also be empty.

Execute the migration again and check the database.

If we do a rollback just for fun

Copy code The code is as follows:
php artisan migrate:rollback

The excerpt column is gone.

The above is the entire content of this article. I hope it will help everyone master the Laravel5 framework.

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