Decision Center provides two schemas for you to define the structure of your extension model and data files, and a default extension model and data file on which to base your custom rule model extension files.
The rule model defines the artifacts that are managed in a rule project. These artifacts have associated properties with various types. The rule model is integrated into Rule Designer, in the Rule Development Toolkit (RDT), and in a Decision Center database schema. You can extend the rule model to provide new artifact types and properties.
You can define rule model extensions to create a new type of business rule or rule package, or to add properties to existing rule model classes.
Rule model extensions are common to Rule Designer and Decision Center, so you can define an extension once for both environments. You then integrate the rule model extension into Rule Designer or Decision Center and then synchronize the extensions of the two environments. When you publish RuleDocs from Decision Center, your rule model extensions are also available in Rule Solutions for Office.
You can also insert your own code, at specific extension points: for example, to hide a specific property, or to call some code after a property value is changed.

You define rule model extensions with XML files. The main XML file is the extension model file, which defines the structure of the extension. You can associate an extension data file to the extension model file, which defines the values of enumerations or hierarchies. You must then register these files in Rule Designer and Decision Center.
Two schemas are provided to define the structure of your extension model and data files:
extensionmodel.xsd
extensiondata.xsd
Decision Center provides default extension model and data files. You can use the content of these files as the basis for your custom rule model extension files.
In these files, the following properties are set:
| Rule model class | Property | Type | Values (defined in the extension data file) |
|---|---|---|---|
| Rule | effectiveDate | Date | - |
| expirationDate | Date | - | |
| status | Status | new, defined, validated, rejected, deployable | |
| BusinessRule | priority | String | The value of the priority property must be interpretable as an Integer, that is, either it must be an Integer, or a value that can be converted into an Integer following the Java™ language specification. |
The properties of Rule and BusinessRule are put into the ruleset when you extract it.