Administration spécialisée > Personnalisation des objets métier > Administration des règles d'initialisation d'un objet > Understanding Object Initialization Rules > Object Initialization Rules Overview
  
Object Initialization Rules Overview
The use of object initialization rules provides a way for administrators to specify the following:
Attribute value generation -- The value defined for a specific attribute associated with an object type can be a constant or a value that is generated at runtime.
Some clients, such as the Windchill workgroup managers, use attribute value generation to request a value for an attribute (such as a number) before an object is stored in the database. For more information, see CAD Document Numbering.
Default values for object initialization -- When objects are being stored in the database, Windchill uses the established object initialization rules to set the values for the attributes that do not already have a value.
The default values are used only when the user interface creating the object does not set a value or when the user interface requests a server generated value. For example, you can set the default values for folder paths, life cycle templates, numbering, and versioning that are then used in generating the values for the user interface. The functionality in the current user interface for creating objects provides the intended results; modifying the out-of-the-box rules that are set may affect the functionality if the value is not set by the user interface.
Display characteristics that constrain attribute values -- If the user interface checks for the constraints, they are then used when the attribute value is displayed in the user interface. For example, the constraints for numbering is honored in the user interface that creates parts (object type: WTPart).
The out-of-the-box constraints include the ability to:
display a value that the user cannot change (immutable).
obtain a value that can be displayed in the interface as the default value (server pregenerated).
not display a generated value, but only display the word generated (server assigned).
not display the attribute label or value (hidden).
Rule variables -- When you want to use the same value for multiple attributes, you can define a variable to hold the results of a calculation and then use the variable when setting default values or defining constraints for attributes.
A variable cannot depend on the value of any other variable. For additional information, see Variables.
These specifications for the attributes are called rules. Each rule can contain the specification of both attribute values and constraints for one object type. The rules are created using XML elements.
Additionally, you can qualify when values are set or when constraints are used for Windchill attributes by integrating the use of conditional logic algorithms in object initialization rules.
The following sections provide information on rules that are loaded during installation, how to add rules, how rules work, and the content of the rules (including information on numbering and versioning).