PowerDesigner15.1 tips 4

PowerDesigner15.1 tips 4

PowerDesigner15.1 tips 4

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PowerDesigner15.1 tips (1)
PowerDesigner15.1 tips (2)-how to find official resources
PowerDesigner defines cdm, ldm, and pdm

The data structure of a table is represented by a tree structure.

This type of link is called a recursive link. You can use relationship to direct to yourself.

Entities can be associated through Relationship. Based on the number of ing relationships between entities, links can be divided into One-to-One, One-to-Many ), multiple-to-multiple connections, Recursive Relationship, and Identify Relationship.

Basic Terms of the tree:

Root Node (maximum degree) branch node (degree not 0) leaf node (degree 0) Data Type

Cdm and ldm entities do not display data types

Define non-display type

Entity Properties-> Attributes-> Customize Columns and Filter-> Data Type remove check box

Display non-display type

Tools-> Display Preference... -> Entity-> Data Types
Like visio, It is set globally rather than a single attribute.

Definition of data type
It can be defined as needed. For example, the data type of a field is abc, but a prompt is displayed.

How to name a relationship

The relationship name cannot be empty or repeated. Generally, the names of two tables are combined.
For example, teacher_student. For more information, see Conceptual dimo-basics.

Set Foreign keys

In relationship.
Cdm is generally unavailable, and ldm is available.

Line display

It seems that the location of the link line of the pd is not automatically adapted, and the link line cannot be automatically aligned. You must adjust it manually.

Description of IdentifierIdentifier_1

Read the official documentation. It should be the key.

Remove show Identifier_1

Tools -> Display Preference... -> Entity -> Identifiers

Inheritance placement

It is best to inherit the parent class above and the Child class below. I have tried to place it between left and right, which is hard to understand.

How to inherit from the same subclass

Double-click inheritance-> more-> children-> add children-> check to confirm

Display of fields during inheritance

The Logical Data Model uses inheritance. When a physical data model is generated, only child classes can be generated without parent tables.
See http://www.cnblogs.com/studyzy/archive/2011/08/16/2140675.html

Other Data Items

Concept model is available, ldm is not. Each field name can only appear once. That is to say, the same field name indicates the same meaning.
For example, if Table A has field T1 and table B also has field T1, you change table A to T2!

Field removal display

Tools -> Display Preference... -> Entity -> Mandatory

Default black line function

I think it is good to differentiate modules.

The difference between cdm and ldm includes entity and relationship, but cdm only has relationship. ldm can be divided into relationship and n-n relationship entity. After both the table name and field contain inheritance entity, cdm will generate Data Items on the left, while ldm will not Data Items. If the field name is the same, it will not be merged; if the code is the same, it will automatically merge existing Data Items, just enter the code, other fields will be automatically generated and deleted. Data Items will not be deleted (it feels like a bug). There are no restrictions on inheritance in cdm, in ldm, it is strictly restricted that the entity in cdm and ldm cannot be copied to each other, and the field can also be copied to each other. The color is the same as that in cdm with association, ldm is designed without the correct process of using cdm and ldm, and ldm is generated based on cdm. If the cdm is to be modified, it can only be directly modified on the ldm. Ldm can distinguish between cdm and ldm elements by color.