Entering the composition of a Meta Entity (Type) or Meta Data Aggregate

The composition of a Meta Entity, Meta Entity Type, or Meta Data Aggregate must be specified in the Composition tab. This tab is common to the Meta Entity, Meta Entity Type, and Meta Data Aggregate editors. For the Meta Entities, the information that is entered in this tab defines the structure of the User Entities. In this tab, you define the composition of the Meta Data Aggregates that are used in Meta Entities. You also specify the composition of a Meta Entity Type that is used to extend a standard entity.

About this task

A Meta Entity, Meta Entity Type, or Meta Data Aggregate sometimes has several description levels. A description can call a child description, which can in turn call a child description. All Meta Entity descriptions must contain a root element that can be a data aggregate description or a data description. The root element is unique. You cannot change its cardinality. A data aggregate description root can contain data aggregate descriptions, data descriptions, Data Elements (in the Pacbase facet), Data (in the COBOL facet), or Meta Data Aggregates.

Procedure

  1. Open the Composition tab of the instance.
  2. If the Composition pane is empty in a Meta Entity or Meta Entity Type, it means that no description has been added. To create a description root, click Add and select Add data aggregate description. Enter a name and a label in the Data aggregate description section opens. For a Meta Data Aggregate, the root is created automatically. It takes the name of the Meta Data Aggregate and cannot be modified or deleted.
  3. Click Add again and select Add data aggregate description to create the first data aggregate description. This description can contain data descriptions, Data Elements (in the Pacbase facet), Data (in the COBOL facet), and Meta Data Aggregates.
  4. Then, click Add and select Add data description to insert data description at this level of the tree structure. You must enter a type, a definition, the allowed values, and the intervals in the Data Description section that automatically opens.
  5. To insert a Data Element or Data call in the description tree, click Add and select Add Data Element (in the Pacbase facet) or Add Data (in the COBOL facet). In the selection wizard that opens, click an instance or create an instance. The new instance must be defined in its dedicated editor. You can also add Meta Data Aggregates by following the same procedure.
  6. To create another description level in the tree, click the data aggregate description root and click Add. Select Add data aggregate description. Give the description a name and a label. The number of descriptions in a Meta Entity or Meta Data Aggregate is not limited.

What to do next

CAUTION:
You are strongly advised against modifying a Meta Entity when it contains User Entities. It might cause errors.

Do not forget to complete the fields in the definition panes that open when you insert or select a composition line in the tree.

When the composition of Meta Entity Type is modified and saved, the description of the entity that is associated with the Meta Entity Type is automatically updated. For example, if you modify the composition of a "Program 3" Meta Entity Type that extends a Program entity, the "Program 3" tab is updated in the Program entity.


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