PowerDesigner concept Data Model CDM

Source: Internet
Author: User
Tags powerdesigner
The concept data model (ConceptualDataModel) is also called the information model. It is based on the object-link theory and expanded.

The concept Data Model (Conceptual Data Model) is also known as the information Model. It is based on the object-link theory and expanded.

The concept Data Model (Conceptual Data Model) is also known as the information Model. It is based on the object-link theory and expanded. It models the information Data from the user's perspective, it is mainly used for Conceptual Design of databases. People abstract the real world into a conceptual world, and then convert conceptual data into a computer-understandable model;

CDM is a set of strictly defined model elements that accurately describe the static characteristics, dynamic characteristics, and integrity constraints of the system, it contains three parts: data structure, data operation, and integrity constraint;

General features of the data model:

1. Data feature abstraction in the real world;

2. It simulates the real world;

3. easy to understand;

4. Convertible, implemented by computer;

Drawing the CDM diagram when the customer purchases the product

Create CDM


Create entity


Attribute settings


Feature Recognition


Select the primary (secondary) identifier attribute check box (define different identifiers for each object)

Create data items that can be attached to an object as attributes of the object (minimum unit of information storage)

Set Unique code options and Reuse options for data items: Unique code. Each data item has a Unique code in the same namespace. Allow Reuse can act as attributes of multiple objects;

An object is successfully drawn.

The relationship between multiple entities. The split end of the line represents multiple, and the split end represents one, the small circle represents an optional, and the small cross end represents a force;


Multiple entities are successfully drawn.

Contact Us

The content source of this page is from Internet, which doesn't represent Alibaba Cloud's opinion; products and services mentioned on that page don't have any relationship with Alibaba Cloud. If the content of the page makes you feel confusing, please write us an email, we will handle the problem within 5 days after receiving your email.

If you find any instances of plagiarism from the community, please send an email to: info-contact@alibabacloud.com and provide relevant evidence. A staff member will contact you within 5 working days.

A Free Trial That Lets You Build Big!

Start building with 50+ products and up to 12 months usage for Elastic Compute Service

  • Sales Support

    1 on 1 presale consultation

  • After-Sales Support

    24/7 Technical Support 6 Free Tickets per Quarter Faster Response

  • Alibaba Cloud offers highly flexible support services tailored to meet your exact needs.