change_table

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.

change_table(:suppliers) do |t|
  t.column :name, :string, limit: 60
end

change_table(:suppliers) do |t|
  t.integer :width, :height, null: false, default: 0
end

change_table(:suppliers) do |t|
  t.timestamps
end

change_table(:suppliers) do |t|
  t.references :company
end

Creates a company_id(integer) column.

change_table(:suppliers) do |t|
  t.belongs_to :company, polymorphic: true
end

Creates company_type(varchar) and company_id(integer) columns.

change_table(:suppliers) do |t|
  t.remove :company
end

change_table(:suppliers) do |t|
  t.remove :company_id
  t.remove :width, :height
end

change_table(:suppliers) do |t|
  t.remove_index :company_id
end

See also Table for details on all of the various column transformation.

Links:

doc_ruby_on_rails

2025-01-10 15:47:30

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