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The difference between rake db:migrate and rake db:reset is pretty clear in my head. The thing which I don't understand is how rake db:schema:load different from the former two.

Just to be sure that I am on the same page:

rake db:migrate - Runs the migrations which haven't been run yet.
rake db:reset - Clears the database (presumably does a rake db:drop + rake db:create + rake db:migrate) and runs migration on a fresh database.

Please help to clarify, if my understanding has gone wrong.

jiroch · Accepted Answer · 2015-11-27 14:27:48Z

db:migrate runs (single) migrations that have not run yet.
db:create creates the database
db:drop deletes the database
db:schema:load creates tables and columns within the (existing) database following schema.rb
db:setup does db:create, db:schema:load, db:seed
db:reset does db:drop, db:setup

Typically, you would use db:migrate after having made changes to the schema via new migration files (this makes sense only if there is already data in the database). db:schema:load is used when you setup a new instance of your app.

I hope that helps.

UPDATE for rails 3.2.12:

I just checked the source and the dependencies are like this now:

db:create creates the database for the current env
db:create:all creates the databases for all envs
db:drop drops the database for the current env
db:drop:all drops the databases for all envs
db:migrate runs migrations for the current env that have not run yet
db:migrate:up runs one specific migration
db:migrate:down rolls back one specific migration
db:migrate:status shows current migration status
db:rollback rolls back the last migration
db:forward advances the current schema version to the next one
db:seed (only) runs the db/seed.rb file
db:schema:load loads the schema into the current env's database
db:schema:dump dumps the current env's schema (and seems to create the db as well)
db:setup runs db:schema:load, db:seed
db:reset runs db:drop db:setup
db:migrate:redo runs (db:migrate:down db:migrate:up) or (db:rollback db:migrate) depending on the specified migration
db:migrate:reset runs db:drop db:create db:migrate

For further information please have a look athttps://github.com/rails/rails/blob/v3.2.12/activerecord/lib/active_record/railties/databases.rake (for Rails 3.2.x) andhttps://github.com/rails/rails/blob/v4.0.5/activerecord/lib/active_record/railties/databases.rake (for Rails 4.0.x)

Here is the file with answers :) - github.com/rails/rails/blob/master/activerecord/lib/… — cutalion, Apr 24 '12 at 16:54
@cutation: db:setup does surely not run db:migrate, because it would be much too brittle to run all migrations just for a db setup (this is what schema.rb is for). — moritz, Apr 25 '12 at 9:10
I'm executing db:reset and it's seeding my db. Why could it be? — Alejandro Riedel, Feb 11 '13 at 0:17

Simon Bagreev · Answer 2 · 2012-04-24 16:25:21Z

As far as I understand, it is going to drop your database and re-create it based on your db/schema.rbfile. That is why you need to make sure that your schema.rb file is always up to date and under version control.

Douglas G. Allen · Answer 3 · 2015-02-07 18:20:18Z

You may find all the db do stuff in this file on github these days.

https://github.com/rails/rails/blob/4-2-stable/railties/lib/rails/tasks/engine.rake

If you really want to have some SQL fun try doing a structure dump.

SashaEgorov · Answer 4 · 2015-09-03 13:58:15Z

Thanks for valuable post. As I found from this discussion there is only one way to recreate DB from migrations sequence i.e. NOT form db/schema.rb. This way is the following:

rake db:drop && rake db:create && rake db:migrate && rake db:seed

Precisely. Not sure why its posted as an Answer, instead of a comment! — Gaurav Agarwal, Sep 4 at 9:00

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2015년 11월 30일 월요일

Difference between rake db:migrate db:reset and db:schema:load

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2015년 11월 24일 화요일

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