Flowdock
change_table(table_name) public

A block for changing columns in table.

Example

 # change_table() yields a Table instance
 change_table(:suppliers) do |t|
   t.column :name, :string, :limit => 60
   # Other column alterations here
 end
Examples
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

Show source
Register or log in to add new notes.
September 25, 2008
18 thanks

All methods

change_table :table do |t|

  t.column # adds an ordinary column. Ex: t.column(:name, :string)
  t.index # adds a new index.
  t.timestamps
  t.change # changes the column definition. Ex: t.change(:name, :string, :limit => 80)
  t.change_default # changes the column default value.
  t.rename # changes the name of the column.
  t.references
  t.belongs_to
  t.string
  t.text
  t.integer
  t.float
  t.decimal
  t.datetime
  t.timestamp
  t.time
  t.date
  t.binary
  t.boolean
  t.remove
  t.remove_references
  t.remove_belongs_to
  t.remove_index
  t.remove_timestamps
end