Specialized Administration > Tailoring Business Objects > Object Initialization Rules Administration > Working with Object Initialization Rules > About Object Initialization Rules
  
About Object Initialization Rules
By using object initialization rules, an administrator can:
Specify default values for attributes of an object type.
The default values are then used when the Windchill solution creates objects of that type but only when the user does not set a value for the attribute through the user interface.
Specify constraints that determine whether the user interface used to create a particular type of object has special display characteristics for any of the attributes associated with the object. Applying a constraint on an attribute can provide the user interface with the following characteristics:
Immutable -- User cannot change the attribute value that is being displayed.
Server assigned -- User interface does not display a value for the attribute; the value is generated and assigned when the object is saved.
Pregenerated -- User interface displays a value for the attribute. The value is generated before the attribute is presented in the user interface.
Hidden -- User interface does not display a value or label for the attribute.
Discrete set -- User interface is constrained to picking from a discrete set of values. This is also known as an enumerated list.
The display characteristics that are available for attributes using object initialization rules provide a capability similar to specifying constraints on attributes from within the Type and Attribute Management utility. For additional information on using constraints on attributes, see Constraints Tab.
For more information about limitations in specifying constraints, see Configuring Rules.
You can set default values and specify constraints in XML documents. Each XML document that is uploaded using the Object Initialization Rules Administration utility is considered a rule. Each rule can contain default values and constraints for the attributes defined for one object type.
Additionally, you can use conditional logic within a rule to identify when a specific default value or constraint is used, and you can use rule variables to hold the results of calculations and then use the variables to set default values or define constraints for attributes. This is useful when you want to use the same value for multiple attributes.
Rules are defined within contexts and only affect objects stored within those contexts or child contexts, allowing the rules for a specific object type to be different in each organization, product, library, project, and program.
The related links listed below provide information on rules that are loaded during installation, how to add rules, and how to accessing the Object Initialization Rules Administration utility.
For how rules work, see Merging Rules to Create a Composite Rule.
For how to specify a rule, see Specifying Rules.
For additional reference information, see Understanding Object Initialization Rules.