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Tools for identifying changes to a MySQL schema
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Rakefile no base May 26, 2013


mysql-inspector is a command line tool that helps you understand your MySQL database schema. It works by writing a special type of dump file to disk and then parsing it for various purposes.


mysql-inspector supports several useful commands, but the first thing you'll want to do is write at least one copy of your database to disk.


Write a copy of your database to disk for mysql-inspector to operate on. You can name this copy whatever you want, by default it's called current.

mysql-inspector write my_database

The result of this command will be a directory full of .table files at ./current, one for each table in your database. A .table file is a simplified and consistent representation of a table. Most importantly, it will not change arbitrarly like a mysqldump file if the order of columns changes or an AUTO_INCREMENT value is defined on the table. mysql-inspector is purely concerned with the relational structure of the table and favors this over an exact representation of the current database schema. In practice, this means that you can commit this directory to source control and easily view diffs over time without excess line noise.


Search your entire database for columns, indices and constraints that match a string or regex. For example, find everything that includes 'user_id' to see which tables relate to a user.

mysql-inspector grep user_id
mysql-inspector grep '^name'

Multiple matchers may be specified, which are AND'd together.

mysql-inspector grep first name


Compare two schemas against each other. Perhaps your local development and production databases have gone out of sync. First write a copy of each and then let mysql-inspector show you the tables and attributes that differ.

By default, a diff is performed on dumps named current and target.

mysql-inspector write dev_database current
mysql-inspector write prod_database target
mysql-inspector diff


Restore a version of your database schema. By default, the current schema is used.

mysql-inspector load my_database

Rails and ActiveRecord Migrations

mysql-inspector can help you manage your database schema in a Rails project. It replaces rake tasks such as db:structure:dump and writes its own version at db/current instead of db/structure.sql. You'll find this format much more convenient for checking into version control.

When a schema_migrations table is found, mysql-inspector writes its contents to a file called schema_migrations within the dump directory. When a dump is loaded via mysql-inspector load or rake db:structure:load, the migrations will be restored.


Ryan Carver (@rcarver /


Copyright © 2012 Ryan Carver. Licensed under Ruby/MIT, see LICENSE.

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