Defining A Key Constraint - Sybase PowerDesigner XML User Manual

Defining identity constraints

Defining a key constraint

66
A key constraint specifies that an element or an attribute value (or set of
values) must be a key within a specified scope.
A key means that data should be unique, not null and always present within a
specified scope.
For example:
Generated schema:
The KEYCODE key constraint, defined on the project element, specifies that
the code attribute must be unique, not null and always present within the
product element.
To display a key property sheet, double-click its name or its icon in the
Browser tree view.
PowerDesigner