change_table(table_name, options = {})
Instance Public methods
A block for changing columns in
table
.
# change_table() yields a Table instance change_table(:suppliers) do |t| t.column :name, :string, limit: 60 # Other column alterations here end
The options
hash can include the following keys:
-
:bulk
-
Set this to true to make this a bulk alter query, such as
ALTER TABLE `users` ADD COLUMN age INT(11), ADD COLUMN birthdate DATETIME ...
Defaults to false.
Add a column
change_table(:suppliers) do |t| t.column :name, :string, limit: 60 end
Add 2 integer columns
change_table(:suppliers) do |t| t.integer :width, :height, null: false, default: 0 end
Add created_at/updated_at columns
change_table(:suppliers) do |t| t.timestamps end
Add a foreign key column
change_table(:suppliers) do |t| t.references :company end
Creates a company_id(integer)
column.
Add a polymorphic foreign key column
change_table(:suppliers) do |t| t.belongs_to :company, polymorphic: true end
Creates company_type(varchar)
and
company_id(integer)
columns.
Remove a column
change_table(:suppliers) do |t| t.remove :company end
Remove several columns
change_table(:suppliers) do |t| t.remove :company_id t.remove :width, :height end
Remove an index
change_table(:suppliers) do |t| t.remove_index :company_id end
See also Table for details on all of the various column transformation.
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