Attribute

Every entity and relation may have many attributes. Clicking on in the Data tab panel of the class or association will add a new row in the related field table. This row includes columns for the attribute name and the domain datatype, together with several metadata columns for the new attribute. Figure 7 shows the Data tab panel while creating an attribute.

Figure 7: Adding an attribute to a class.

Similar to classes, attributes of the same name in different schemas are considered different. Attributes of the same name within the same schema represent the same attribute, even if defined in different classes or associations.

The domain of an attribute is indicated in the column after its name. To change the domain, just type the new datatype name in this field. There does not exist a predefined set of domains. They are represented simply as strings. Unlike classes and associations, domain has a global context. Domains of the same name in different schemas are considered the same domain.

Attributes can be deleted from a class or an association by selecting the respective row in the field table at the Data tab panel, and then clicking on the button.