1. In the Data Model Explorer, expand the Logical Main Model, right-click the Entities node, and then double-click the entity to which you want to add keys.
2. To change the properties of an existing attribute, In the Entity Editor, click an attribute you want to make a key and then click Edit.
To create an alternate key or inversion entry based on a new attribute, in the Entity Editor, click Add and define the entity properties as required.
3. On the Keys tab, click Add.
4. In the Key Editor, type a name for the key and select the type of key you want to create.
5. From the list of Available Keys, which are all the attributes of the entity, double-click the attributes you want to add to the key.
Tip: You can reorder the attributes by selecting an attribute and then pressing Up or Down until the attribute is in the desired position within the list of Selected Keys.
6. Click OK to accept the attribute selections and then click OK again to affect the changes to the entity.
Attachment Bindings tab: Bind an external piece of information, or attachment to the key. You can also remove an attachment from an object, override an attachment binding’s default value, or change the position of a bound attachment. To override the value of the attachment you have moved to the Selected Attachments grid, double-click the Value field of the target attachment. ER/Studio DA opens the Value Override Editor or a list depending on the attachment datatype. Attachments are created in the Attachments folder of the Data Dictionary. For more information, see Attaching External Documents to the Data Model.