Normalization and Redundacy Suggest one (1) of the problems that normalization s

Question

Normalization and Redundacy

Suggest one (1) of the problems that normalization seeks to solve within a database. Describe one (1) example of your suggested problem, and explain the overall benefit that normalization would provide. (Note: Your example can be hypothetical or use the university business function/operation.)

Identify the key determinants that could affect the degree of normalization of a database. Justify your response. Next, identify the aspects of the database design that can be denormalized. Explain the key ways in which the business rules support the degree of normalization and the elements that can be denormalized.

Explanation / Answer

1 -

The database does not have redundant data, it is smaller insize so less money needs to be spent on storage

# There is less data to search through, it is much faster to run a query on the data.

# There is no data duplication.

# There is better data integrity and less risk of mistakes.

# There is less chance ofstoring two or more different copies of the data.

# Once change can be made which can instantly be cascaded across any related records.

2 -

Lets take an example of a database which holds information of companies.

The information of a company includes Company Name, Owner, Registration No., Address, and so on … , and these are all single value data.

You can put all these data in a table like this :

A01 Company, Owner 01, Reg. No. 01, Address 01

A02 Company, Owner 02, Reg. No. 02, Address 02

A03 Company, …

And now you find that each company includes some multiple value data, like its Employees and their Phone Numbers. One company can has multiple of employees and multiple phone numbers.

Then the problem now is that how would you like to organize these multiple value data with the single value data together.

One way is to put all data in the same table, and becomes like this:

A01 Company, Owner 01, Reg. No. 01, Address 01, Employee A, Phone A

A01 Company, Owner 01, Reg. No. 01, Address 01, Employee B, Phone B

A02 Company, Owner 02, Reg. No. 02, Address 02, Employee C, Phone C

A02 Company, Owner 02, Reg. No. 02, Address 02, Employee D, Phone D

A02 Company, Owner 02, Reg. No. 02, Address 02, Employee E, Phone E

…

You will find that there is a lot of redundancy of data. And you will think of store the data in two separate tables, and that is what is called normalization.

The first table holds the single value data:

A01 Company, Owner 01, Reg. No. 01, Address 01

A02 Company, Owner 02, Reg. No. 02, Address 02

…

And the second table holds the multiple value data:

A01 Company, Employee A, Phone A

A01 Company, Employee B, Phone B

A02 Company, Employee C, Phone C

A02 Company, Employee D, Phone D

A02 Company, Employee E, Phone E

…

The two tables are related or linked to each other by Company Name.

Reducing the redundancy of data means reduced database size. Manipulation of data also becomes more convenient because there is no need to handle the redundant data of the multiple value records.

3 -

A determinant in a database table is an attribute that can be used to determine the values assigned to other attributes in the same row. By this definition, any primary key or candidate key is a determinant, but there may be determinants that are not primary or candidate keys.

For example, a company might use a table with the attributes <Employee_id>, <First_name>, <Last_name> and <Date_of_Birth>.

Employee_id - 1, 2, 3, 4

First_name - ajay, bijay, rekha, sushma

Last_name - Brown, miller, jones, davis

Date of Birth - 1/1/1980, 2/2/1981, 3/3/1982, 4/4/1983

In this case, the field <Employee_id> determines the remaining three fields. The name fields do not determine the <Employee_id> because the firm may have employees that share the same first or last name. Similarly, the <Date_of_Birth> field does not determine the <Employee_id> or the name fields because employees may share the same birthday.

In this example, <Employee_id> is a determinant, a candidate key, and also a primary key. It's a candidate key because when the entire database is searched for 2, the row containing the information about Bijay millerr appears and no other record is shown.

4 -

The aspects of the database design that can be denormalized are as follows.

• Always create a conceptual data model that is completely normalized.

• Denormalization boosts performance.

• Never presume denormalization will be required.

• To meet performance objectives, denormalization should be done during the

database design.

• Once performance objectives have been met, do not implement any further

denormalization.

If you have any more dificulties feel free to ask me again. if you found this answer helpful please vote Up !

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