3. Metamodel & Class Definitions

The metamodel is not your target but provides the backbone to interconnect your enterprise data. Designer is model agnostic. Just make sure, you have the metamodel in place to answer your business questions.

Designer Admin Rights Required

Ensure your target metamodel is implemented in ServiceNow and you have a good idea about all interdependencies required. Please check, if the following is in place in ServiceNow before you proceed:

  • Tables (sys_db_object)
  • Relationship Types (cmdb_rel_type)
  • Suggested Relationships (cmdb_rel_type_suggest)

Don't be the show-stopper! Tables & Relationships are essential

You need to understand and govern the tables & relationships used by your target audience. Otherwise Designer users will not find the essential data, and can't perform their job creating outstanding Diagrams & models.

Defining & Creating Class Definitions

Class Definitions are mandatory to define the tables which are visible within the Repository Browser to query and insert ServiceNow data. The Class Definitions are essential to define the default styling per table, too.

Designer is installed with over 100 pre-configured Class Definitions. Please go to the Class Definitions Table and activate/deactivate those required respectively create new Class Definitions.

Class Definitions Table


The quickest way to create a Class Definition by leveraging the shape styling is the following:

  • Open the shape.
  • Click the “Create Class Definition” UI Action.

Class Definitions Form


A – Activate the class definition to make it visible in the Diagrams browser.

B – The category helps you to group different shapes logically. The choice fields can be changed by an administrator. This category is not visible anywhere else.

C – Name of the table / class visible in the Designer browser.

D – Field which will be displayed as the shape name and search result of the repository browser.

E – Default width of the shape used when loading data from the browser.

F – Default height of the shape used when loading data from the browser.

G – Each class definition can be assigned to a domain, where it will be only visible for the domain and sub-domain members. Class definitions assigned to the global domain will be visible to all users in all domains.

H – The style definition for the specified table/class. Use CTRL+E on a shape to copy its styling.

I – Selected Class Fields which are available to store additional information on future state elements. See here for further information.

We do not like redundancy

Avoid redundant Class Definitions. Deactivate not required ones.

Domain Separation Support

The class definitions table supports domain separation. Please enable plugin Domain Support – Domain Extensions Installer (com.glide.domain.msp_extensions.installer) to separate data and configuration.

Set Cross Scope Privileges

Designer is a scoped application and requires ‘Cross Scope Privileges’ to be able to read tables or create entries in tables (commit) if required.

In order to support the automatic creation and management of Cross-Scope Privileges through Class Definitions, please ensure that the Application Access (Can Read, Can Create, Can Update, Can Delete) is set correctly on the sys_db_object table.

Alternatively, download the following UpdateSet to set the Application Access:


To set the Cross-Scope Privileges automatically:

  • Open a Class Definition.
  • Select “Read Table” to allow Designer to read that table.
  • Select “Allow Commit” to allow Designer to create items in that table during the commit operation.