1 Select File > New Diagram. Select Entity Relation or IDEF1X from the displayed list of choices. or
2 In the explorer, right-click Diagrams. Select Entity Relation or IDEF1X from the displayed list of choices.
Enter the name of the diagram to be created, and then click OK.
Assigning the Diagram to a Project Model vs Subject Model.
Each ER diagram must either be a project-level model diagram or a subject area diagram assigned to a project model. You may not leave the model name blank.
3 Indicate whether the diagram will be a subject area or a model diagram by toggling the appropriate radio button in the Diagram Status field. Subject area diagrams are part of a model. The Model diagram is an aggregate of all subject area diagrams in that Project Data Model.
4 Enter the name of the project data model in the Model field or click on the Choices button and drag the name of an existing project model into the text box.
5 Select a DBMS Field popup type, and then click OK.