Chapter 3 Building Conceptual Data Models

Defining additional check parameters for objects in a CDM

You define additional check parameters for data constraints where standard check parameters are not sufficient.

Example

An entity in a data model for a clothing shop may contain check parameters defined for an entity attribute SIZE, which depend on the check parameters defined for another entity attribute COUNTRY, as clothing size for a skirt in France may be different from the same size in the United States.

In this case an expression is required to create a constraint which uses check parameters defined for both entity attributes.

To define additional check parameters for objects:

1. Open the property sheet of a domain or entity attribute and click the Additional Checks tab.
   
2. Type a SQL expression, which may include any of the following variables:
   
   
   • %MINMAX% - Minimum and maximum values defined in Values groupbox on Standard Checks tab
   • %LISTVAL% - Customized values defined in List Values groupbox on Standard Checks tab
   • %RULES% - Validation rule expression defined on Expression tab of the Rules property sheet
3. Click OK to return to the model diagram.

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