After completing the chapter, you will be able to design a DB2 database.
You will look at the concept of database design with the real life example.
Say your database is like a custom home and that you are going to have one built for us. What is the first thing you are going to do? Certainly you are not going to hire a contractor immediately and let him build our home however he wishes. Surely you will first engage an architect to design your new home and then hire a contractor to build it.
The architect will express your needs as a set of blueprints, recording decisions about size and shape, and requirements for various systems (structural, mechanical, electrical). Next the contractor will procure the labor and materials, including the listed systems, and then assemble them according to the drawings and specifications.
Now let’s return to your database perspective and think of the logical database design as the architectural blueprints and the physical database implementation as the completed home. The logical database design describes the size, shape, and necessary systems for a database; it addresses the informational needs and operational needs of your business.
You then build the physical implementation of the logical database design, using your RDBMS software program. Once you have created your tables, set up table relationships, and established the appropriate levels of data integrity, our database is complete. Now you are ready to create an application that allows interacting easily with the data stored in the database and you can be confident that these applications will provide with timely and above all, accurate information.
It is possible to implement a poor design in an RDBMS, but a well designed database will yield accurate information, store data more efficiently and effectively, and will be easier to manage and maintain.
If a database is designed improperly, users will have difficulty in retrieving certain types of information, and there is the added risk that searches will produce inaccurate information. Inaccurate information is probably the most detrimental result of improper database design. It can adversely affect the bottom line of a business.
In fact, if the data kept and used in a database is going to affect the way a business performs its day-to-day operations or if it's going to influence the future direction of the business, database design must be a concern.
Designing the database involves:
Logical Database Design
Physical Database Design
Implementing and Altering Database Design
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