Migration From an Existing Database | Laravel

tags: database, laravel

Intro

I got a mission to clone an existing service, which has its database separately from the original.

Here is my to-do list:

1. create tables
2. sync data

This article will only record the first step. the next step will be written in the second episode.

How to create tables from the existing database

Since this project is a Laravel app, but without migration files so I came out with 2 solutions:

1. Create migrations from the existing database, then run php artisan migrate to create the same tables to my new database
2. Create create-table-SQLs from the existing database, then somehow run these SQLs

Migration Generator

I thought the first one is more ideal since it is easier for other developers to maintain so I googled "laravel create migration …" then google returned me a bunch of packages to do these tasks, nice!

here is a couple of choices:

• composer package:
  • https://github.com/Xethron/migrations-generator
  • https://github.com/barryvdh/laravel-migration-generator
  • https://github.com/adamkearsley/laravel-convert-migrations
• online convertor
  • https://laravelarticle.com/laravel-migration-generator-online

So I generated all the migrations in seconds, lovely!
Then I run php artisan migrate!

CRASH!

Checked out the migrations, found that the generator didn't generate the codes properly. It missed some details, like lacking index, so I needed to go through each file to debug… which was not my purpose to use a tool so I tried the second solution, create tables by pure SQL

How to Execute SQL Files in Laravel

It is easier than I thought

use Illuminate\Support\Facades\DB;

DB::unprepared(file_get_contents('path/to/sql.sql'));

I test a table and it worked properly, created exactly same table as the original without error

Implement

So I exported the table structure in SQL from phpMyAdmin manually (the total number of tables is still acceptable for me to do this).

Instead of creating a command to do this task, I still generated migrations matched to the tables since I would like to have the ROLLBACK feature in Laravel migration. Remember? We can create migrations in seconds by using one of the mentioned packages. Don't forget to edit .env to switch to the original database, And after generating, switch back to the NEW database.

Here is my migration code. I put all the SQL in database/sql_migrations but you can put them anywhere you like.

<?php

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

class CreateNewTable extends Migration {

    /**
     * Run the migrations.
     *
     * @return void
     */
    public function up()
    {
        $sqlpath = 'database/sql_migrations/'.basename(__FILE__, ".php").'.sql';
            Illuminate\Support\Facades\DB::unprepared(file_get_contents($sqlpath));
    }


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

}

After all files are set, we can easily run php artisan migrate to create tables, and php artisan migrate:rollback to rollback.

Sync Data From an Existing Database | Laravel