Build a physical diagram from the logical model built in the previous module.
There are two main reasons for separating logical and physical database design:
▪to enable modeling of normalized and denormalized designs
▪to enable modeling of distributed databases
Database Denormalization
When designing a database system, it is often advantageous to adhere to the rules of data normalization during the logical design stage. This assures that data redundancy is minimized.
Only if you separate the logical and physical design stages, can the logical design be normalized even though the physical data model is denormalized.
Database Distribution
Distributed systems are logically one database system, but physically multiple database systems. Separation of logical and physical models allows distributed databases to be effectively modeled and reported on.
In System Architect, you can create a Project Data Model comprised of multiple subject area ER diagrams, each of which represents a different database in the distributed system. Then you can generate a physical model from each entity relation subject area diagram.
Learning objectives
After completing the lessons in this module you will know understand the concepts and know how to:
▪create a physical data model
▪model constraints between tables
Time required
This module should take approximately 15 minutes to complete.
Prerequisites
To complete this module, you will need to have the Tutorial encyclopedia open. If you need directions on how to open prebuilt encyclopedias, or this encyclopedia is not attached to your server, refer to the Introduction section of this module.
Model a constraint in your physical data model to demonstrate the constraints between a guest of a hotel, and their vehicle. Enter the room number of a guest as the role name. Respond to error messages.