Entity-Relationship Diagram Editor

This editor enables you to create or modify an Entity-Relationship Diagram (ERD) or the Entity-Relationship Model (ERM). For more information see the Information Modeling Reference manual.

The Entity-Relationship Model represents the whole data model, for example the model of the company data. You can choose which E-R Diagrams to include in the E-R Model. It is one diagram showing all Relationships between all Entities from the model under consideration. You create the Entity-Relationship Model by importing Entity-Relationship Diagram output files (using the In command). The E-R Diagram files must have been created using the Out command.

Pull-down Menus

The ERD/ERM editor contains the following pull-down menus:

File

Edit

View

Draw

Options

Popup Menus

There are also popup menus available within the Entity-Relationship Diagram/Model editor. These are activated by pressing the right mouse button. A different menu appears depending on the pointer position, relevant to the operations that are appropriate to the currently selected object and pointer position. There is a different menu for when you are:

pointing to an Entity

pointing to a Weak Entity

pointing to a Relationship

pointing to an IS_A Relationship

pointing to a Connection

pointing to a Rolename

pointing to a Cardinality

pointing to a Connection Point

pointing within a selection frame

pointing to Text

not pointing to a diagram object

In the last situation, ProMod-PLUS assumes that you want to Create an object.

Double-click on graphical objects

If you double-click on a graphical object this carries out the most commonly used command. The command started is different if you double-click on the label of an object or on the symbol excluding the label. For example, if you double-click on the name of an Entity this carries out Alter on the Entity name. If you double-click on the Entity symbol outside the Entity name this carries out Connect.

The following table shows the full list of commands carried out when double-clicking on objects.

Symbol

Label

Entity Connect Alter
Weak Entity Connect Alter
Relationship Connect Alter
IS_A Relationship Connect ---
Connection Alter Alter
Text --- Alter