Check Constraints

ModelRight allows you to create both Table and Column Check Constraints.  A Check Constraint object is owned by the Table or Column that it is applied to.  You can also create Check Constraint Templates so that you can specify a constraint in one place and then reuse it throughout your Model - via inheritance.  To have a Column or Table Check Constraint reuse a Check Constraint Template, simply select it in the Inherit control.   In ModelRight, a Table Check Constraint can either be an Expression or a Script:

Expression - enter a Boolean expression involving the Table's Columns.  Double-click on a Column in the Available Columns control to add the Column's name to the Expression edit control.

Script - enter a VB Script that will be evaluated to produce the Check Constraint.

A Column Check Constraint contains a few more options: Min/Max, Valid Values List, and Not Null:

Min/Max - specify a min condition and value and/or a max condition and value

Valid Values - Valid Value Lists are defined as independent objects (children of the Model) and just referenced/attached here.  To quickly create and attach a new Valid Values List object, click the Create New... button.

Not Null - a Not Null Column Check Constraint is automatically created and deleted by ModelRight  based on the NOT NULL checkbox control in the Column Property Page.