Creation of Table Constraints 

Use

You can use the wizard in the modeling environment for Variant Configuration to create constraints for evaluating variant tables. This is particularly useful if you are unfamiliar with the syntax or if you want to create a general framework quickly and then extend it with the syntax editor.

For a general overview of constraints, see Constraints.

Integration

To be able to assign constraints, you need a constraint net. The wizard creates this constraint network automatically.

Prerequisites

To be able to create a constraint, you need a classified material and at least one configuration profile.

Table constraints are based on variant tables. When you create a table constraint, you can use the wizard to create the required variant table too.

Variant Tables in the Worklist

When you create a table constraint using the wizard and want to use an existing variant table, you have to explode the model completely (see Worklist), because the wizard searches for existing variant tables in the worklist only.

Features

You can use the wizard to create table constraints for five different applications. Detailed descriptions with examples are provided in the F1 Help for the applications that the wizard proposes for selection when you create a constraint. The following applications are available:

Value Restriction

The value range of a characteristic is restricted on the basis of value combinations that are listed in a variant table.

This constraint can be used with restrictable characteristics only.

Value Derivation for a Target Characteristic

A unique value for a specific characteristic (target characteristic) is derived from a set of characteristics that have been assigned values. The variant table contains both the values of the target characteristic and the characteristic values that define the target.

Value Derivation from a Guiding Characteristic

When a value is assigned to a specific characteristic (also known as a guiding characteristic), other characteristics are derived. The variant table contains both the values of the guiding characteristic and the values of the derived characteristics.

Selective Value Derivation

When a value is assigned to a set of characteristics, which are regarded as input characteristics, unique values are derived for other characteristics, which are then regarded as output characteristics. The variant table contains the values of both the input and output characteristics.

Check for Inconsistent Combinations

If one of the characteristic value combinations listed in the variant table arises, it triggers a configuration conflict. The variant table lists the inconsistent combinations.

Activities

You can launch the wizard for creating table constraints from the context menu for the following objects in the model tree:

·        Material

·        Configuration profile

·        Constraint net

·        Class

Example

Take the configurable material “Electric Drill” as an example. You have classified the material and created a configuration profile, but have yet to create a variant table. Your model has the following characteristics and characteristic values (among others):

Characteristics	Characteristic Values
Use	Home Professional
Voltage	110 V 400 V
Motor (invisible characteristic)	M_4711 M_4712 M_4713

You want to use a table constraint to derive the correct motor as soon as the user chooses a “voltage" and "use" in the interactive configuration process.

Creating a Table Constraint with the Wizard

To create the table constraint, proceed as follows:

...

       1.      Select the material in the model tree and choose Create Table Constraint with Wizard… from the context menu.

The wizard is displayed in a separate window that has two parts:

¡        The area on the left shows the sequence of steps you need to follow to create the constraint, as well as the current status. To go back to a step you have already completed (for example, to correct an entry or change a decision), all you have to do is click it.

¡        Each step is explained in the top right of the window.

¡        In the area on the right, you can choose parameters and edit names and descriptions.

¡        You can navigate through the step sequence using the  Continue and  Back pushbuttons.

       2.      Choose Value Derivation → Value Derivation for a Target Characteristic. Choose  Continue.

       3.      In the table displayed, choose the “Motor” to make it the target characteristic. Choose  Continue.

       4.      Choose the “Use” and “Voltage” characteristics in the table to make them the input characteristics in the variant table.

Enter a name and a description of the variant table. Choose  Continue.

       5.      The wizard then shows the input characteristics “Use” and “Voltage” on the area on the left, and the target characteristic “Motor” in the area on the right. Together, these entries form the structure of the new variant table.

Select the indicator for mandatory derivation of the target characteristic. By doing so, you can make sure that a configuration conflict is displayed whenever the target characteristic cannot be derived during the interactive configuration process. You are in the “Conditional Execution” step.

Choose  Continue.

       6.      The wizard now displays a suggested explanation for the table constraint. Change the text if necessary and choose  Continue.

       7.      Enter a name and description for the table constraint. Choose  Continue.

       8.      An overview of the properties of your table constraint is now displayed. If necessary, you can go back to the step for naming the variant table, for example, to change the name or description. If you are happy with all the properties of your constraint, choose  Complete to create the table constraint.

Editing the Variant Table

You have used the wizard to generate a table constraint for deriving the target characteristic “Motor” and create the structure of a variant table with the input characteristics “Use” and “Voltage”.

To enable the table constraint to derive the target characteristic using the variant table, you now have to edit the contents (rows) of the variant table. In other words, you have to specify the value combinations that define the target characteristic.

To edit the variant table, proceed as follows:

...

       1.      If you have not already done so, open the detailed view of the variant table.

For more information about working with tables, see Variant Tables.

       2.      Insert three rows to derive the target characteristic values “M_4711”, “M_4712”, and “M_4713”.

       3.      Combine the input characteristic values with the target characteristic values in the variant table as follows:

Use (Input)	Voltage (Input)	Motor (Target)
Home	110 V	M_4711
Professional	110 V	M_4712
Professional	400 V	M_4713

The table does not contain the combination “Home” and “400 V”, for example. If the user chooses this combination, a conflict will be displayed because the target characteristic cannot be derived but is mandatory in this example.

Model Tree

The table constraint is displayed in the model tree under the constraint net, which was created automatically by the wizard, or under an existing standard constraint net.

Use the context menu to remove the dependency from the model.

Detailed View

To check or edit the table constraint, open the detailed view of the table constraint.

Tab Page	Function
Basic Data	Here, you can edit the description, status, group, and authorizations.
Editor	Use the editor if you want to edit the source code of the table constraint; see also Editing of Dependencies. By doing so, you can also reset the mandatory value derivation (see above) by activating the condition created automatically.
Texts	Here, you can edit the language-dependent descriptions.