Creating a Nested Hierarchy of Models

The INCLUDE command allows you to include one model within another model. A model can contain only one INCLUDE command. The INCLUDE command must come before any equations in the model, and it can specify the name of just one model to include. The model that contains the INCLUDE command is referred to as the parent model. The included model is referred to as the base model.

You can nest models by placing an INCLUDE command in a base model. For example, model m1 can include model m2, and model m2 can include model m3. The nested models form a hierarchy. In this example, m1 is at the top of the hierarchy, and m3 is at the root.

Working with the INCLUDE Command

If a model contains an INCLUDE command, then it cannot contain any DIMENSION commands. A parent model inherits its dimensions, if any, from the DIMENSION commands in the root model of the included hierarchy. In the example just given, models m1 and m2 both inherit their dimensions from the DIMENSION commands in model m3.

The INCLUDE command allows you to create modular models. If certain equations are common to several models, then you can place these equations in a separate model and include that model in other models as needed.

The INCLUDE command also facilitates what-if analyses. An experimental model can draw equations from a base model and selectively replace them with new equations. To support what-if analysis, you can use equations in a model to mask previous equations. The previous equations can come from the same model or from included models. A masked equation is not executed.

After you compile a model, either by running it or by using the COMPILE command, you can run an OLAP DML program called MODEL.COMPRPT to produce a report on the structure of the compiled model. If you run MODEL.COMPRPT after compiling a model that contains a masked equation, then you will find that the masked equation is not shown in the report.