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You will learn basic PowerDesigner techniques for creating a CDM, including:

How to create the basic elements of a CDM: domains, data items, business rules, and entities

How to create different types of relationships between entities

How to create packages and add objects to a package

How to create an inheritance

How to use the display functions to arrange symbols and to center the model on the page

How to generate a Physical Data Model (PDM) from a CDM

CDM Getting Started

 

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Before you begin, make sure that the files you need for the exercises are on your hard disk. When you install PowerDesigner, these files are installed in the Examples\Tutorial directory of PowerDesigner. When you have finished with this tutorial you can delete them if you want.

The CDM tutorial uses the following files:

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CDMBEFOR.CDM

Starting tutorial CDM

CDMAFTER.CDM

Finished tutorial CDM

 

 

 

PowerDesigner

C H A P T E R 2

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The first step to creating a Conceptual Data Model (CDM) is to formulate a

 

statement of the business problems that the CDM will address. To do this,

 

you draw up a description of business activities. This helps you decide:

 

What information you need to store

 

What entities are involved in the business

 

How the business operates

 

When the way the business operates is clear, you can begin to develop the

 

CDM.

Business

You will start this tutorial with a CDM that is the conceptual model of the

description

information system for a publishing company.

 

A business description indicates that the entities involved in the business

 

include titles, authors, book stores, and discounts. It indicates the details

 

related to each of these entities: from international standard book numbers

 

(ISBN) for titles to store addresses.

Business problem In the course of the CDM tutorial, you will solve three business problems:

5R\DOWLHV IRU PXOWLSOH DXWKRUV Keep track of different royalty

 

percentages for authors of the same book

$XWKRU SLFWXUHV DQG ELRJUDSKLHV Identify and store author pictures

 

and biographies for use on book covers

7LWOH FDWHJRULHV Classify each title as a periodical or a non-periodical and save related information

On the basis of these business problems, you will extend the tutorial model to manage additional data. For example, you will add an entity for pictures and you will create a data item to store information about percentages of royalties that a particular author receives.

CDM Getting Started

 

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PowerDesigner

C H A P T E R 3

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You will begin the tutorial by running PowerDesigner. You will learn how to use the tool palette.

You will open the tutorial file and assign it preferences, options, and properties. Next, you will save it under a different name so that you can go back and use the original model again if you want to repeat the exercises.

What you will do

In this chapter you will:

 

Start PowerDesigner

 

Use the tools in the tool palette

 

Open the tutorial CDM

 

Define CDM preferences and options

 

Define CDM properties

Save the tutorial CDM

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About 10 minutes.

CDM Getting Started

 

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Click the 3RZHU'HVLJQHU program icon.

The PowerDesigner main window appears. It contains an object browser window docked to the left, and an output window docked to the bottom of the main window.

The object browser window shows the contents of the workspace in a tree view. You can use the object browser to organize the objects in each of your models.

The ZRUNVSDFH is the name for the current PowerDesigner session.

Workspace is the default node in the object browser tree view. The new

CDM that you will open will be created and saved in a workspace.

The output window shows the progression of any process that you run from PowerDesigner, for example the process of generating a PDM from a CDM is shown in this window.

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All the screen captures in this book were taken with a resolution that may be different from the one you use, as a result the appearance and proportions of the images on your screen may be slightly different.

 

PowerDesigner

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1Select )LOH1HZ.

A selection window appears. It lists the types of models that you can open in the PowerDesigner main window.

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3Click 2..

A CDM model window appears. It contains a diagram window (as yet empty), a palette, and the Browser and Output windows are docked to the left and bottom of the screen respectively.

CDM Getting Started

 

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The buttons in the CDM tool palette enact all major functions needed to build and modify a CDM.

The following table indicates the names and functions of each tool in the palette:

 

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Pointer

Selects symbol

 

 

Lasso

Selects symbols in an area

 

 

 

 

Grabber

Selects, moves and resizes all symbols

 

 

 

 

Zoom In

Increases view scale

 

 

 

 

Zoom Out

Decreases view scale

 

 

 

 

Open Package Diagram

Display diagram for selected package

 

 

 

 

Properties

Display property sheet for selected symbol

 

 

 

 

Delete

Delete symbol

 

 

 

 

Package

Insert package symbol

 

 

 

 

Entity

Insert entity symbol

 

 

 

 

Relationship

Insert relationship symbol

 

 

 

 

 

 

PowerDesigner

 

 

 

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Inheritance

 

Insert inheritance symbol

 

 

Association

 

Insert association symbol

 

 

 

 

 

Association Link

 

Insert association link symbol

 

 

 

 

 

File

 

Insert a file symbol

 

 

 

 

 

Note

 

Insert note symbol

 

 

 

 

 

Link/Extended

 

Draws a graphical link between symbols in

 

 

 

 

 

Dependency

 

the diagram

 

 

 

 

Draws a note link between a Note and an

 

 

 

 

object

 

 

 

 

Draws an extended dependency between two

 

 

 

 

objects that support extended dependencies

 

 

Title

 

Insert title symbol

 

 

 

 

 

Text

 

Insert text

 

 

 

 

 

Line

 

Draw a line

 

 

 

 

 

Arc

 

Draw an arc

 

 

 

 

 

Rectangle

 

Draw a rectangle

 

 

 

 

 

Ellipse

 

Draw an ellipse

 

 

 

 

 

Polyline

 

Draw a jagged line

 

 

 

 

 

Polygon

 

Draw a polygon

 

 

 

 

 

 

 

 

 

So that you know how to use these tools before you begin creating the CDM, you will create a few objects using the tool palette.

1Click the (QWLW\ WRRO in the tool palette.

The cursor takes the form of an entity when it is moved into the diagram.

2Click anywhere in the CDM diagram.

CDM Getting Started

 

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An entity symbol appears at the click position. The entity has the name Entity_Q, where n is a number assigned to the entity in the order of creation of objects.

3The Entity tool is still active, so click again in the CDM diagram to create another entity.

There are now two entities in the CDM diagram.

4Click the 5HODWLRQVKLS WRRO in the tool palette.

The Entity tool is now released and the Relationship tool is active.

5Click inside the ILUVW HQWLW\ and while continuing to hold down the mouse button, drag the cursor to the second entity. Release the mouse button inside the second entity.

This creates a relationship.

6Click the ULJKW PRXVH EXWWRQ. You release the relationship tool.

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A tool remains active until you release it. You can release a tool, by selecting another tool or by clicking the right mouse button. By default, when you click the right mouse button, the Pointer tool is activated.

7Click the /DVVR tool in the palette. The Lasso tool is now active.

8Click the cursor above a corner of the first entity and while continuing to hold down the mouse button, drag the cursor so that you draw a rectangle around the two entities.

Release the mouse button.

 

PowerDesigner

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