method
change_table
Ruby on Rails latest stable (v7.1.3.2)
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1 note -
Class: ActiveRecord::ConnectionAdapters::SchemaStatements
change_table(table_name, base = self, **options)
public
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
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Set this to true to make this a bulk alter query, such as
ALTER TABLE `users` ADD COLUMN age INT, ADD COLUMN birthdate DATETIME ...
Defaults to false.
Only supported on the MySQL and PostgreSQL adapter, ignored elsewhere.
Add a column
change_table(:suppliers) do |t| t.column :name, :string, limit: 60 end
Change type of a column
change_table(:suppliers) do |t| t.change :metadata, :json 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(bigint) 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(bigint) 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 transformations.
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RobinWu -
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