Application of PowerDesigner (1): Application of powerdesigner

Application of PowerDesigner (1): Application of powerdesigner

The conceptual data model is also called the Information Model (Entity-RelationShip, referred to as E-R). It is based on the Entity-link theory and expands this theory. It models information from the user's point of view and is mainly used for Conceptual Design of databases. Generally, people first abstract the real world into a conceptual world, and then convert the conceptual world into a machine world. In other words, the objective object in the real world is first abstracted into the Entity and Relationship. It does not depend on a specific computer system or a DBMS system, this model is what we call CDM, and then converts CDM to the data model supported by a DBMS on the computer. This model is the physical data model, that is, PDM.

First, let's look at how to build CDM:

1. Choose file --> new. In the displayed dialog box, select CDM, as shown below:

2. Select Entity in the toolbar and click it on the panel. An Entity instance is displayed. You can double-click the object to modify the object name in the pop-up "Treasure General" tab. On the Attributes tab, you can add Attributes for an object as follows:

3. After the object is created, find the RelationShip (Link) in the toolbar and add a link between the objects (click an object and do not release the mouse key to drag another object), as shown below:

Double-click the added link to set the corresponding properties between entities, as shown below:

4. Generate the PDM model. Select generate PDM under the tool as follows:

Result of generating PDM: