Attributes
Entities and associations can be characterized by attributes.
An attribute is a named property of a class. This is the most basic data saved in the enterprise information system.
These attributes can be found by studying the content of messages circulating within the enterprise.
Examples:
• "Client Name" (property of the client entity).
• “Client No.” (identifier of the client entity).
• “Account Balance” (property of the account entity).
An attribute characterizes an association when the attribute depends on all the entities participating in the association.
In the diagram below, the role that a “Consultant” plays in a “Contract” depends on the consultant and on the contract, and therefore on the “Intervene” association.
Defining attributes
To create an attribute on an entity:
1. In the data diagram, right-click the entity and select Attributes.
The entity properties dialog box opens.
2. To add a new attribute to the entity, in the
Attributes tab, click the
button.
A default name is automatically proposed for the new attribute. You can modify this name.
You can specify its Type.
Example: Numeric value.
A datatype is used to group characteristics shared by several attributes.
Inherited attributes
When a generalization exists between a general entity and a more specialized entity, the specialized entity inherits the attributes of the general entity.
See “Attribute and Column Types", page 145 for more details on types that can be assigned to an attribute.