A good database design is the key to efficient and reliable end-user application.

Database design determines the way how data should be stored and how it should be related. If you keep in mind the objectives of good database design while going through each and every step then it will help you avoid many problems that may be faced due to poor designing. Always follow a good database design methodology as it will help you recognize the errors before you go too deep into them. A good database design will save hours of development time and the database to maximum extent will meet the user requirements.

One day a client of mine asked me why database development takes time. And I replied not all database but a good database design takes time so that once I hand over it to you then you need not to come back again and again.

In this article I will answer the question that why do we need a good database design? I am sure that this article will be helpful for you while designing your databases.

1. A good database design models all requirements:

A good database design models all the requirements and identifies all potential problems. This should not be the case that after some days your requirements change and you have to change database design from scratch. A good database design fulfils all the requirements.

2. A good database design contains Normalized tables:

A good database design contains normalized tables. Normalized tables results in efficient and flexible database structures. It removes the problem of redundancy and the data is easy to maintain.

3. A good database design is resistant to anomalies:

A good database design does not suffer from update, insert and deletion anomalies. If database tables are normalized then there will not be problematic changes at any point.

A good database design does not result in logical inconsistencies when same information is updated in multiple tables.

4. A good database design models efficient database:

A good database design models an efficient database. If your database design is good then your tables will be normalized and the queries will be optimized. Your database will not take much time in populating results.

5. A good database design supports defined and undefined queries:

A good database design supports both required and ad hoc queries. It should have defined as well as undefined functions. Your database must store all relevant and important information. If any ad hoc query is asked by the user at any point then your database must be able to answer it.

Appropriate planning plays an important role at this step. If you properly follow the planning phase then you will be able to identify all possible requirements. This will ensure that you do not miss any important data.

6. A good database design ensures data integrity:

A good database design supports data integrity. If there is no data redundancy then data integrity will be maximally ensured. The minimal is data redundancy the least will be inconsistencies.

7. A good database design is data independent:

A good database design is independent of data. For example any time the record format is changed. A data type of a field is changed or a field is added, dropped or updated then you don't have to change each and every program that accesses that data. If you change the 7 digit registration id to 11 digit registration id then all your programs must be able to read and process the new records.

8. A good database design fulfils all business requirements:

A good database design supports business rules relevant to client it is developed for. It should contain accurate and up to date data.

9. A good database design has flexible structure:

A good database design is flexible for future developments. With time being the requirements of the client may change and some developments may be required in the database. A good database design has flexible structure that does not create any problems while expansion of the database. You can easily add new functionalities delete or update older ones without need to do everything from scratch. Any modification in the table or field will not affect the overall system.

10. A good database design is not complex:

A good database design is not complex. It is easy to maintain and easy to retrieve data. The queries will be optimized and there will be minimal join queries. You do not need to join so many tables and form a complex query in order to retrieve results. You can easily modify and maintain the structure of tables and fields.

11. A good database design minimizes the development phase:

A good database design aids in easy development of end-user applications. You do not have to worry about so many problems that arise due to poor database design and hence the development phase will be reduced.

Sources:

1. http://www.schools.ash.org.au/olshc/infotech/dbdesign.htm
2. http://science.nature.nps.gov/im/datamgmt/dm2002/DBDesign.ppt
3. http://www.ercb.com/feature/feature.0014.html
4. http://en.wikipedia.org/wiki/Database_normalization
5. http://www.island-data.com/downloads/papers/normalization.html
6. http://www.informit.com/store/product.aspx?isbn=0201694719&rl=1

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