The derived instances

You can create a derived instance from a reference instance and use this derived instance to generate the reference instance with different generation parameters, without duplicating its design.

Derivation is available for the following entities: Program, Screen, Server, Data Structure (for the generation of the Copybooks and the error messages), Dialog (for the generation of the error messages), and Server Dialog.

It is useful when an instance must be generated with different generation parameters. You use it, for example, to generate a Program for CICS and for IMS. So, you create a derived instance that points to a reference instance and to a generation Library. This derived instance does not contain any design. You can then generate the reference instance from another Library without duplicating its design.

To create the derived instance, you must use the creation wizard of the entity. For example, you use the Program creation wizard to create an instance that is derived from a Program instance. Enter its required fields and check the Create a derived entity box. Then, specify the instance that it is derived from in the <Entity> to derive field.
Tip: You can leave the Name empty, check the Create a derived entity box, and enter the reference instance. The name of the derived instance is then automatically initialized with the name of the reference instance. You need to complement this name with the Library or any other distinctive code. This way, they can be easily associated among all the available instances.

The derived instance is displayed in the Design Explorer view, under the entity it is derived from. Double-click the instance to open its editor.

Then, you must generate the derived instance. It generates the reference instance but with the generation parameters of the Library that is selected in the derived instance.
Note: If the design of the reference instance has been modified, the generation of the derived instance takes this modification into account, except if the change was only a change of Library.

Feedback