Most of the objects in the logical model correspond to a related object in the physical model. For example, the logical model contains entities, attributes, and key groups, which are represented in the physical model as tables, columns, and indexes, respectively. In the following table, see how logical and physical components compare in a typical model:
|
Logical Model |
Physical Model |
|
Entity Dependent entity |
Table FK is part of child table's PK |
|
Attribute Logical datatype (text, number, datetime, blob) |
Column Physical datatype such as char(18), int, or varchar |
|
Domain (logical) |
Domain (physical) |
|
Key Group Primary key (PK) |
Index PK (in model) and PK Index (in schema) |
|
Relationship Identifying |
Relationship implemented using FKs FK is part of child table's PK (above the line) |
|
Not applicable |
View or View Relationship |
|
Not applicable |
Pre- and Post-script |
Note: You can specify whether an object is included in the logical model only, the physical model only, or both, by using the Logical Only and Physical Only check boxes in the corresponding property editor.
|
Copyright © 2013 CA.
All rights reserved.
|
|