Chapter 4: Designing the Database

Chapter 4: Designing the Database

Overview

Now that we have learned how to create a database, it is time to learn how to create all the different types of objects that exist inside an Oracle8 database, such as tables, indexes, clusters, constraints and triggers. At the end of this chapter we should have a database that is ready to accept data.

Schemas

Before we define any tables in our database, we must first understand the concept of schemas in the database. A schema is a logical construct which describes a collection of objects. Schemas are a nice way of grouping together the various components of the database. For example, suppose our database holds customer and order information. One approach would be to create two schemas, one for customers and the other for orders. In the customer schema, we would find the customer table and index. In the order schema, there might be tables and indexes for the order, order lines, products and warehouse tables.

How many schemas the DBA defines is a design decision. If your database is only going to contain information pertaining to one area of the company, then a single schema would suffice. But if you are going to hold data from various areas, then it is wise to consider how many schemas would be needed.


	Hint	It is very important to make the decision at the outset of the design because the schema name plays an integral part in retrieving and storing data in...

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Oracle8 on Windows NT

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Chapter 4: Designing the Database

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