How to reposition a new column in rails 3.x migration

Question

I created a hyphen that just adds a new column, but I want it to be added before the created_at and updated_at columns, is there any way to indicate at what position the new column is being created?

I searched and only found someone to say to use the: after option in add_column but does nothing. then I looked in the rails api docs and did not find such an option.

Answer 1

After the option works well for me

add_column :table_name, :column_name, :type, :after => :column_name 

Also see this question .

Answer 2

From my research, the option :after does not work for SQLite or Postgres , since these DBMSs do not allow such an operation. However, this option works for MySQL .

Literature:

• SQLite: https://www.sqlite.org/lang_altertable.html - this basically tells you to create a new table with the correct column ordering, then copy the data.

• Postgres: https://wiki.postgresql.org/wiki/Alter_column_position