method

add_unique_constraint

v7.1.3.2 - Show latest stable - 0 notes - Class: SchemaStatements

1.0.0
1.1.6
1.2.6
2.0.3
2.1.0
2.2.1
2.3.8
3.0.0
3.0.9
3.1.0
3.2.1
3.2.8
3.2.13
4.0.2
4.1.8
4.2.1
4.2.7
4.2.9
5.0.0.1
5.1.7
5.2.3
6.0.0
6.1.3.1
6.1.7.7
7.0.0
7.1.3.2 (0)
7.1.3.4 (0)
7.2.3 (0)
8.0.0 (38)
8.1.1 (0)
What's this?

add_unique_constraint(table_name, column_name = nil, **options) public

Adds a new unique constraint to the table.

add_unique_constraint :sections, [:position], deferrable: :deferred, name: "unique_position"

generates:

ALTER TABLE "sections" ADD CONSTRAINT unique_position UNIQUE (position) DEFERRABLE INITIALLY DEFERRED

If you want to change an existing unique index to deferrable, you can use :using_index to create deferrable unique constraints.

add_unique_constraint :sections, deferrable: :deferred, name: "unique_position", using_index: "index_sections_on_position"

The options hash can include the following keys:

:name: The constraint name. Defaults to uniq_rails_<identifier>.
:deferrable: Specify whether or not the unique constraint should be deferrable. Valid values are false or :immediate or :deferred to specify the default behavior. Defaults to false.
:using_index: To specify an existing unique index name. Defaults to nil.

Show source

# File activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb, line 744
        def add_unique_constraint(table_name, column_name = nil, **options)
          options = unique_constraint_options(table_name, column_name, options)
          at = create_alter_table(table_name)
          at.add_unique_constraint(column_name, options)

          execute schema_creation.accept(at)
        end

add_unique_constraint

Related methods