Migrating mysql data across schemas in Django (or anything else)

Posted on May 23, 2013

I’m aware there are solutions made to avoid this, but I found myself in the situation of only having data in mysql backups. Hopefully the following will be useful to others who fall into the same situation.

Generate mysqldump of the remote database:

    mysqldump -u cody -h corys.dbserver.com -pmypassword name_of_database

Create the database on the same server as the database data is being migrated to.

    mysqadmin create dump_db

Insert the data

    # disable foreign key checks
    set foreign_key_checks = 0;

    # insert data and foreign key data
    insert ignore into newapp_model select * from dump_db.oldapp_model;
    insert ignore into newappmodel_modelfield select * from dump_db.oldapp_modelfield;

    # enable foreign key checks again
    set foreign_key_checks = 1;

Test that the data works in the Django shell

    python manage.py shell

    In [14]: [g.genre for g in Movie.objects.filter(title="transformers")[0].movie_genre.all()]
    Out[14]: 
    [<Genre: Action>,
     <Genre: Adventure>,
     <Genre: Science Fiction>,
     <Genre: Thriller>]

Last Step: Repeat.

There are undoubtedly better ways of doing this, but it didn’t this method didn’t take very long. More importantly, it worked :D