I know how to add one column to an existing table. Now I have to add many columns to an existing table. Is there a shorter way for:
add_col1_col2_col3_col4_.._coln_to_tables col1:integer col2:integer etc...
Do I have to do the above for ALL the additional columns I have to add?
No not necessary. You can do
Assuming TableName is user
rails g migration AddColumnsToUser col1:integer col2:integer .. etc.
Here's a good resource on ActiveRecord:Migrations which lists all the commands you can use to manipulate your databases. You can also do the task this way:
rails g migration AddMoreColumnsToModel
Then open the migration file and put:
def change
add_column :table, :new_column, :type
# add as many columns as you need
end
If you wanted to do what Maxd suggests, having literally 100 columns of the same type auto-create, his code is a good idea.
Just create migration and generate these columns i.e.:
class ChangeTables < ActiveRecord::Migration
def change
change_table :tables do |t|
100.times do |i|
t.integer :"column_#{i}"
end
end
end
end
Similar to above answers but for understanding purpose hope below naming convention is good.
rails g migration add_first_column_and_second_column_to_model first_column:string second_column:string
This migration file can be done in a loop. But do you really want to do this? It does not look correct to create such a heavy model to hold everything.
command to create new model and table with columns:
rails g model ModelName col_name1:string col_name2:integer col_name3:text ...
command to add more columns under existing table:
rails g migration AddColumnToModelName col_name4:string col_name5:integer ...
At last, run migration by command:
rake db:migrate
