Introduction

A strong database design is one of the primary factors in establishing a database that will provide good performance while minimizing the use of resources. One of the first steps after gathering information about a particular scenario is to begin the preparations of a database design by first determining its logical design. A logical design involves mapping out a database through the analysis of entities , relationships , and attributes . This is known as Entity Relationship modeling , which will be the first focus of this chapter.

Designing a good database does not require the knowledge of how databases are specifically implemented in SQL Server. In fact, often the logical design is prepared before any determination of the actual software to be used for the data storage. In cases where the software is predetermined, this should be taken into consideration during the logical design. Any particular limitations and features of the specific product would be handled as needed.

Preparing an appropriate database design often depends on how well you can comprehend a given scenario. Techniques are laid out through this chapter to help you comprehend and get information from a sample scenario. However, knowing the physical tasks for implementation of databases is necessary only when you want to apply and create the database in SQL Server. This chapter discusses the basic elements of a logical database structure. It also looks ahead to where and how the logical model evolves into the physical database itself.

Determining the database model, or ER-model on how tables relate to each other is known as putting together the logical database design, because you are just brainstorming how a database will be designed. When implementing the database itself onto SQL Server, you are applying the logical design to implement the physical database, which is the focus of the next chapter. In looking at the logical implementation, you must have a thorough understanding of relational databases themselves . The details of the physical SQL Server objects are in the next chapter, and the implementation of much of the physical side to databases is covered throughout this entire book.

This chapter also looks at some of the basics of application architectures. A variety of models for how a database is used and how SQL Server fits into a multiple data source environment are overviewed. Last, this chapter looks into some of the variety of environments that SQL Server fits into, covering database systems that can manage an extremely large quantity of data, users, and a variety of applications.