How dose it work?
LibMigration provides version controll for your MySQL database. This page describes how LibMigration works on your system.
If you don’t know basic usage for LibMigration and have not read Documentation yet. Please read Documentation page before reading this page.
Migration task class
LibMigration create method (or phpmigrate create command) creates migration task class file like the following.
20130702170043_yourdatabase_create_sample_table.php
it’s named using the timestamp of the date your were creaed.
LibMigration sorts task class files by this timestamp to execute your schema change SQL in the correct order.
Schema version table
LibMigration creates a special table in your database. it’s called “schema version table”. it keeps the timestamp of the latest executed migration.
mysql> select * from schema_version; +----------------------+ | version | +----------------------+ | 20130702170043 | +----------------------+ 1 row in set (0.00 sec)
By comparing timestamp of the available migrations, LibMigration can determine the next migration to execute.
The name of “schema version table” in your database can be changed by configuration.
return array(
'colors' => true,
'databases' => array(
'yourdatabase' => array(
...
'schema_version_table' => 'schema_version', // Set table name you like.
...