method

change_table

Ruby on Rails latest stable (v2.1.0) - 1 note - Class: ActiveRecord::ConnectionAdapters::SchemaStatements

v1.0.0
v1.1.0
v1.1.1
v1.1.2
v1.1.3
v1.1.4
v1.1.5
v1.1.6
v1.2.0
v1.2.1
v1.2.2
v1.2.3
v1.2.4
v1.2.5
v1.2.6
v2.0.0
v2.0.1
v2.0.2
v2.0.3
2.1.0 (0)
What's this?

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

# File activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb, line 168
      def change_table(table_name)
        yield Table.new(table_name, self)
      end

September 25, 2008

5 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