Multiple-Column Constraint Format

Use the multiple-column constraint format to associate one or more columns with a constraint. This alternative to the single-column constraint format allows you to associate multiple columns with a constraint.


Multiple-Column Constraint Format

                                .-,------.        
                                V        |        
|--+-+---+-NOT NULL-+-----+--(----column-+--)-+-----------------|
   | |   '-NULL-----'     |                   |   
   | +-+-UNIQUE---------+-+                   |   
   | | |  (1)           | |                   |   
   | | '-------DISTINCT-' |                   |   
   | '-PRIMARY KEY--------'                   |   
   |                  (2)                     |   
   '-| CHECK Clause |-------------------------'

Notes:

Informix® extension
See CHECK Clause

Element	Description	Restrictions	Syntax
column	Name of column or columns on which the constraint is placed	Must be unique in a table, but the same name can be in different tables of the same database	Identifier

This is a subset of the syntax of Multiple-Column Constraint Format that the CREATE TABLE statement supports.

This alternative to the single-column constraint segment of CREATE TEMP TABLE can associate multiple columns with a constraint. Constraints that you define on temporary tables are always enabled.

The following table indicates where you can find detailed discussions of specific constraints.

Constraint	For more information, see	For an example, see
CHECK	CHECK Clause	Defining Check Constraints Across Columns
DISTINCT	Using UNIQUE or DISTINCT Constraints	Examples of the Multiple-Column Constraint Format
PRIMARY KEY	Using the PRIMARY KEY Constraint	Defining Composite Primary and Foreign Keys
UNIQUE	Using UNIQUE or DISTINCT Constraints	Examples of the Multiple-Column Constraint Format