Chapter 18 - Data Model - Visual Paradigm

SDE-VS User’s Guide (Part 2, for ORM) Chapter 18 – Data Model
Chapter 18 - Data Model
You are provided with a visual modeling environment for the data model of an application, and also reverse database
engineering. This chapter shows you how to depict the object models by using Entity Relationship Diagram and how to reverse
database, and describes how the data model maps to the object model.
In this chapter:
18-2
• Introduction
• Creating Data Model
• Reverse Database Engineering
• Creating Array Table in Data Model
• Creating Partial Table in Data Model
• Copying SQL Statements
• Mapping Data Model to Object Model
Introduction
An entity is an object in the business or system with well-defined characteristics which are represented by columns showing
what information can be stored. In relational databases, an entity refers to a record structure, i.e. table.
A data model provides the lower-level detail of a relational database of an application. It shows the physical database models
and their relationships in an application. An entity relationship diagram can be used to describe the entities inside a system and
their relationships with each other; the entity relationship diagram is also known as a data model.
Visual modeling for data models is supported, not only by creating a new data model, but also by transforming from an object
model. Reversing the existing relational model into data models is also supported. As object-relational mapping is automated,
object model can thus be generated from the data model by reversing the existing database.
The following section describes how to reverse the relational model into data models and depict the data models using the
Entity Relationship Diagram.
Entity Relationship Diagram
Entity relationship diagram is a graphical representation of a data model of an application. It acts as the basis for mapping the
application to the relational database.
Creating an Entity Relationship Diagram
You are provided with three ways to create an Entity Relationship Diagram.
1. Drawing an Entity Relationship Diagram(ERD)
2. Reverse Engineering an existing Relational Database
3. Synchronizing from the Object Model to Data Model
Drawing an Entity Relationship Diagram (ERD)
1. You can create a new ERD in one of the three ways:
• On the menu, click File > New > File..., select Entity Relationship Diagram from the New File dialog box.
Figure 18.1 - To create an ERD