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After you have set up migrations for your database you can start using them to generate diffs of your current and your chnaged schema or create your own ones to achieve smooth updates between your schema versions. This chapter will show you how to use migrations in your everyday development cycle.

Generating diffs

Imagine you have set up a database with a User table which holds a fullname column.

 
User:
  actAs:
    Timestampable:  ~
  columns:
    full_name:
      type:         string(255)
      notnull:      true
    email:
      type:         string(255)
      notnull:      true
 

After some time you recognize that using fullname is not applicable anymore since you want to greet the user on your website only by it's first name and not his full one. So changing from a single fullname column to a pair of first_name and last_name columns is needed. To achieve this you can change your schema.yml file to the following as you would always do.

 
User:
  actAs:
    Timestampable:  ~
  columns:
    first_name:
      type:         string(255)
      notnull:      true
    last_name:
      type:         string(255)
      notnull:      true
    email:
      type:         string(255)
      notnull:      true
 

If you now want to apply these changes to your database you can use the doctrine-migrations-diff task to generate the differences between the current and the changed schema. These changes are converted by Doctrine into a migrations file which will be applied to your database the next time you migrate it to a higher version.

 
symfony doctrine:generate-migrations-diff
 

To apply the migrations you have just generated you will have to use the doctrine:migrate task. When called without any parameter this task will use all migrations that need be applied to your database to update it to the current schema.

Applying migrations

 
symfony doctrine:migrate
symfony doctrine:build --all-classes
 

As might have recognized you still have to run the doctrine:build task with the --all-classes switch. This is because your model files won't get updated by the doctrine:migrate task. But as always in symfony there is a way to do this by using a shorter way.

 
symfony doctrine:build --all-classes --and-migrate
 

The doctrine:build task can also take a switch --and-migrate to also migrate your database to the current version along with other operations your perform with it. So this way you will update your database schema and your model files.

This work by Dennis Benkert is licensed under a Creative Commons Attribution-Share Alike 3.0 Unported License.

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