Database in Rails - mnishiguchi/authentication_demo GitHub Wiki

Database in Rails

http://edgeguides.rubyonrails.org/active_record_migrations.html#rolling-back

Database level validation

• Active Record Migrations
• Database level validation - Be The Better Rails Developer
  • Default and Not Null clauses
  • Column indexing
  • Unique column constraints
  • Foreign keys
  • Update statements
  • Multiple inserts/updates
• Available field types

Rolling Back

rake db:rollback

• Executes the drop_table command to remove the users table from the database.
• Works only for reversible migrations by default.
• In the case of an irreversible migration, such as one to remove a database column, it is necessary to define separate up and down methods in place of the single change method:
  • Using reversible
  • Using the up/down Methods