sem-IV

Unit–1 Relational Database Design

ü  Consequences of poor database design

ü  The process of database normalization

ü  Functional dependencies

ü  Lossless joins and dependency preservation

ü  1^st Normal Form, 2^nd Normal Form, 3^rd Normal Form, Boyee-Codd Normal Form

ü  Examples of normalization(Definition with attributes)

v  Consequences of poor database design

1.      Poor design/planning

2.      Ignoring normalization

3.      Poor naming standards

4.      Lack of documentation

5.      One table to hold all domain values

6.      Using identity/guid columns as your only key

7.      Not using SQL facilities to protect data integrity

8.      Not using stored procedures to access data

9.      Trying to build generic objects

10.  Lack of testing

    "If you don't know where you are going, any road will take you there" – George Harrison

Prophetic words for all parts of life and a description of the type of issues that plague many projects these days.

Let me ask you: would you hire a contractor to build a house and then demand that they start pouring a foundation the very next day? Even worse, would you demand that it be done without blueprints or house plans? Hopefully, you answered "no" to both of these. A design is needed make sure that the house you want gets built, and that the land you are building it on will not sink into some underground cavern. If you answered yes, I am not sure if anything I can say will help you.

Like a house, a good database is built with forethought, and with proper care and attention given to the needs of the data that will inhabit it; it cannot be tossed together in some sort of reverse implosion.

Since the database is the cornerstone of pretty much every business project, if you don't take the time to map out the needs of the project and how the database is going to meet them, then the chances are that the whole project will veer off course and lose direction. Furthermore, if you don't take the time at the start to get the database design right, then you'll find that any substantial changes in the database structures that you need to make further down the line could have a huge impact on the whole project, and greatly increase the likelihood of the project timeline slipping.