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 |