1. Product Administration Guide
  2. Set Preference Template

Set Preference Template

The Set Preference template has the form:

When possible, constrain [an expression] to be true with a [specified priority]

The expression in a preference constraint is enforced as a constraint only if it does not conflict with any other constraint type or with any user selections. The purpose of the Set Preference template is to allow you to create soft constraints that guide the Siebel Product Configurator engine in producing solutions but which the engine can ignore if needed to avoid conflicts or performance problems.

A key use for preference constraints is to cause a default selection of Item B based on the selection of Item A. This is called a dynamic default. You can set a default dynamically based on a previous user selection. The user can then override the default if desired by choosing a different item than the dynamic default.

For example, you could write the following constraint:

When possible, constrain [Item A requires Item B] to be true with a priority of [0].

When the user picks Item A, the engine will attempt to create a solution containing Item B. However, the engine is free not to include Item B in order to avoid conflicts and performance problems.

If users do not want Item B, they can remove it without creating a conflict. If you had written the constraint as "Item A requires Item B", Item B would be added when users picks Item A. If user tried to remove Item B, they would receive a conflict message.

Another use for the Set Preference Template is to set or modify the default value for an attribute. To do this, you would write a preference constraint where the expression, is Attribute A = value. The attribute would then be displayed with this value unless overridden by another constraint.

The priority operand in preference constraints determines the order in which multiple preference constraints for an item are evaluated. Preference constraints with priority 0 that apply to a specific item are evaluated first. Those with priority 1 that apply to that item are evaluated next, and so on.

For example, you have written two preference constraints that apply to a specific relationship. PrefConstraint A has a priority of 0. PrefConstraint B has a priority of 1. The Siebel Product Configurator engine will attempt to add PrefConstraint A to the solution before attempting to add PrefConstraint B.

Here is how the Siebel Product Configurator engine creates solutions containing preference constraints:

  • The engine generates a solution that enforces all constraints and user choices but does not include preference constraints.

  • The engine then adds the preference constraints one at a time for each item. It begins by adding the highest priority preference constraints for an item first. Preference constraints with the same priority are added in arbitrary order.

  • If the solution remains valid when a preference constraint is added, then the expression in the preference constraint is enforced as a constraint and becomes part of the solution.

  • If adding a preference constraint creates a conflict so that the solution fails, the preference constraint is skipped, and its expression is not enforced. The engine then goes on to the next preference constraint.

  • Preference constraints are evaluated after all other constraint types and before the engine searches for and sets default attribute values.