Question

One of the characteristics of good relational database design is normalized tables. Discuss two ways in which normalization helps minimize data redundancy and anomalies such as insertion, deletion, and update anomalies.

What are some other characteristics of good database design?

Answer 1

To reduce redandancy and integrity of an relational Database normalization of datatbase is the best process of structuring a relational database in accordance with a series of normal forms. In theNormalization Data is organized in the columns and tables of a database to ensure that their dependencies are properly meets by database integrity constraints

1.> normalization is the process of effectively organising data in a database. There are two main ways of minimizing data redundancy and anamulies for normalization process First is eliminate redundant data i.e storing the same data in more than one table and second is to ensure data dependencies make sense i.e only storing related data in a table. Both of these are effective ways as they reduce the amount of space a database consumes and ensure that data is logically stored.

The normalization techniques reduce anamulies is describes as follows:

1. Update anomaly =>When there is the same information can be expressed on multiple rows; therefore updates to the relation may result in logical inconsistencies. For eg, each record in an "Student' Skills" relation might contain an Student ID, Student Address, and Skill, thus a change of address for a particular Student may need to be applied on the multiple records i.e one for each skill. If there is a condition i.e If the update is only partially successful the Student address is updated on some records but not all other then the relation is left in an inconsistent state and in inintegrity. This method in normalization is known as an update anomaly.
2. Insertion anomaly. There are some situationsin which certain data cannot be recorded at all. For e.g, each record in a "Staff and Courses" relation might contain a Staff ID, Staff Name, Staff Address, and Course Code. so, we can record the details of any Staff member who teaches at least one course, but there can be situation that, we cannot record a newly hired Staff member who has not yet been assigned to teach any courses. This method in normalization is known as an insertion anomaly.
3. Deletion anomaly. Under certain Situations, deletion of data representing certain data necessary todeletion of data representing completely different manner. The "Staff and Their Courses" relation described in the previous example descibes from this type of anomaly, for if a Staff member temporarily ceases to be assigned to any courses, we must delete the last of the records on which that Staff member appears, effectively also deleting the faculty member, unless we set the Course Code to null. This method in normalization is known as a deletion anomaly.

Some other characteristics about good database design

• Use storage space efficiently
• Eliminate redundant data
• Should be able to relate the tables in the database by means of a relation
• Reduce or eliminate inconsistent data
• Ease the database maintenance burden
• Reflects real-world structure of the problem.
• Clean, consistent, and easy to understand.