This method is preferred for writing constructive migrations (adding columns or tables).
The migration knows how to migrate your database and reverse it when the migration is rolled back without the need to write a separate .
when I run rake db:reset, the rescue statement in the first line displays: Warning: not procesing table schema_migrations. I guess I am confused why this statement is rescuing this?
result.first['id'].to_i 1 : 1 puts "Resetting auto increment ID for # to #" Active Record:: Base.connection.execute("ALTER SEQUENCE #_id_seq RESTART WITH #") end at the bottom of the file, which is meant to handle indexing of the seeds file.
So when you switch branches, your is different than your actual db schema.
rake db:migrate will only check the schema version in the and if the database version is then it will run all "pending" migrations.
If the migration's already been applied to the database, yes.This is not the same as running all the migrations. If a migration can't be rolled back, 'rake db:reset' may not help you.To find out more about dumping the schema see 'schema dumping and you.' 'Versions' of migrations are done via timestamps.It only regenerates the file if a migration is run.In the case where your actual schema is at a higher version than the version reported in the it does the only safe thing, which is nothing.by hand but you would then be responsible for telling other developers that they need to go and run them.