Setting Unique Identifiers

Go Up to Business Attributes

You can set a unique identifier for a Business Attributes in the Conceptual model making the entity unique. When exporting to ER/Studio DA, Business Attributes designated as unique identifiers are created as entity attributes with the primary key set to True.

The CASE Method (Barker) notations are used as follows:

• Business Attributes, which are parts of the definition of a unique identifier, are shown preceded by hash marks (#). You can show or hide this indicator, if desired.
• Relationships, which are part of the definition of a unique identifier, are marked by a short line across the relationship near the entity being identified.

In the following example, the unique identifier of Line Item is a combination of the attribute "Line No." and the relationship "part of one and only one Purchase Order." Since the marked relationship represents the fact that each line item is partly identified by a particular purchase order, it implies that the Purchase Order’s unique identifier "PO Number" participates in identification of the Line Item as well. When implemented, a column derived from "PO Number" is generated in the table derived from Line Item. It serves as a foreign key to the table derived from Purchase Order, and is part of the primary key of the table that is derived from Line Item.

Relationships

When you set a Unique Identifier for a Business Attribute, all relationships having the Business Entity containing that Business Attribute as the source gets a new indicator. You can show or hide this indicator, if desired.

Note: If another Business Attribute is set as a Unique Identifier, additional decorators are not added.