Rational Programming Patterns

Data Aggregate Description in a Meta Entity

You can add a Data Aggregate Description in a Meta Entity, Meta Entity Type or in a Meta Data Aggregate. For each Data Aggregate description entered in the composition of these Entities, you must then define its characteristics in the Data Aggregate Description and Component Usage sections. A Data Aggregate is a description which contains other descriptions and Data Elements or descriptions only.

Data Aggregate Description

For a Data Aggregate which is added as the root of the composition in a Meta Entity, you only have to specify its name and label. But for each sub Data Aggregate descriptions, you must specify its usage too.
Name
Enter the name of the Data Aggregate description or Data Element inserted or selected in the composition tree.
Label
Enter a label for the Data Aggregate description.
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Component Usage

Minimum Cardinality
Enter a numeric value to indicate a minimum cardinality. The default value is 0, which means that the description is not mandatory.
Maximum Cardinality
Enter a numeric value to indicate a maximum cardinality. The default value is n for unbounded.
This value indicates the maximum or equal number of occurrences allowed in a User Entity for this current description. The value entered in the maximum cardinality field must be higher than the value in the minimum cardinality field. If it is not, an error will be displayed in your User Entity.
Checks are set on the values entered in these fields. For example, if you define by error a minimum cardinality which is in fact higher than the maximum cardinality, the description icon is marked erroneous in the composition tree. If you move your cursor over the icon, you can read in a tooltip that the maximum cardinality must be higher than or equal to the minimum cardinality.
Identifiers
This table is used to specify the fields which will be set as identifiers in the Data Aggregate description, that is to say, defined as the key. It means that in a User Entity you cannot call more than one description with the same combination of identifiers. Click + to add a field, or click a field and then to remove a field from the table. Click the up or down buttons to modify the list of identifiers in the table.
Important: The cardinality of these identifiers must be (1-1). A presence check will be performed on this field.
Unique
In this table, you can add fields that you set as unique. It means that in two different descriptions, it is not possible to find two fields unique with the same value. As you did for the identifiers, click the + to add a field in the table, or click a field and then to remove a field from the table. Click the up or down buttons to modify the list of unique fields in the table.
Sorts
This table is used to give the order of the descriptions in the User Entity. The descriptions will be sorted in the order given in this table.
Descending
Check this box to get the descriptions sorted descending in the descending order. Clear the box if you prefer an ascending order.

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