Benefits of using Migrations [duplicate]

Question

I'm currently learning a framework that supports Migrations.

My question is: what is the main benefit for using migrations?

Why don't we just use a database adminstration tool to add/drop/alter tables and to do other operations directly? Or why not to just export my .sql file and my team import it in their databases?

Answer 1

Migrations are part of the deployment process. So the benefits of migrations (in general) are

• You don't have to do it manually (because on deployment you probably forget a schema-change sooner or later)
• You can test it locally (because you probably make mistakes sooner or later)
• You don't have to tell your team members to change their local database manually (because thats simply annoying), or import a new dump (again ...)
• If you have multiple environments (stage, prod, test) you have to do this step on any system. This increases the probability of mistakes
• You probably don't want to import the (probably outdated) development-database into the live-system ;)

Note, that in the beginning of a project a schema may be simple and the database small, but this will not stay this. Sooner or later (;)) you will face huge databases, that takes time to import.

Additional: A good migration usually has a "downgrade"-step in case of errors. With your approach if the deployment goes wrong you have to revert your database changes manually, which is even more error prone.

Answer 2

Think of them as version control for your database. It also makes deploying your changes to multiple environments (e.g. Your development environment, then your testing/production server) easy and automatable, rather than having to remember what you did in PHPMyAdmin.

It's easier to tell someone they need to migrate their DB than to have to tell them each individual change they need to make to their DB.