Laravel 5.2 如何在不丢失数据的情况下更新迁移

Question

I'm using laravel 5.2 and I usually update my database according to project requirements, so I'd like to do it without losing database records. I don't mean how to seed my database.. I mean when my database is live and I want to update it throw laravel migration. I was going throw Laravel Documentation but I found nothing, so I hope to find somebody help me

Answer 1

Since you already have data in your tables then instead of rolling back your migrations (which will cause existing data losses) you can create new migration files to update your tables. Suppose you have a table users with columns name, email, password . You stored data in that table. Then you realized that you also do need to add a new column named mobile_no to your users table. To do this you need to create a new migration file. Command will be:

php artisan make:migration add_mobile_no_columns_to_users_table --table=users

This way a new migration file will be created. Set your column details there, run the migrations using php artisan migrate and that's all. You'll have this new column in your users table without losing previously stored data.

Answer 2

请注意，当您在已有数据的情况下为表添加新列时，您必须为新列设置默认值或使其为可为空类型..否则最终会出错

Answer 3

Make sure that when you are adding new column in your table, that column should be nullable, and should not be unique. Otherwise you will face error. Because when a new column is created it will be empty(not unique). In that condition you have to rollback the migration.

Answer 4

Make a new migration with

php artisan make:migration change_body_to_nullable_in_reviews_table --table=reviews

where you put this

    public function up()
    {
        Schema::table('reviews', function (Blueprint $table) {
            $table->text('body')->nullable()->change();
        });
    }

    public function down()
    {
        Schema::table('reviews', function (Blueprint $table) {
            $table->text('body')->nullable(false)->change();
        });
    }

And then run PHP artisan migrate