Let’s learn about the Purpose of Database Systems.
- Data redundancy and inconsistency
- Data redundancy: Data redundancy refers to the duplication of data. For example, if a student is enrolled for two games (Cricket and Volleyball), the same student details in such case will be stored in other games, which will take more storage than needed. This redundancy leads to higher storage and access cost.
- Data inconsistency: Data redundancy leads to data inconsistency, let’s take the same example that we have taken above, a student is enrolled for two games, the same student details in such case will be stored other, now let’s say student requests to change his address, if the address is changed at one place and not on all the records then this can lead to data inconsistency.
- Difficulty in accessing data: Suppose that one of the university clerks needs to find out the names of all students who live within a particular postal-code area. The clerk asks the data-processing department to generate such a list. Because the designers of the original system did not anticipate this request, there is no application program on hand to meet it. However, an application program to generate a list of all students. The university clerk has now two choices: either obtain the list of all students and extract the needed information manually or ask a programmer to write the necessary application program. The point here is that conventional file-processing environments do not allow needed data to be retrieved in a convenient and efficient manner.
- Difficulty in accessing data: Suppose that one of the university clerks needs to find out the names of all students who live within a particular postal-code area. The clerk asks the data-processing department to generate such a list. Because the designers of the original system did not anticipate this request, there is no application program on hand to meet it. However, an application program to generate a list of all students. The university clerk has now two choices: either obtain the list of all students and extract the needed information manually or ask a programmer to write the necessary application program. The point here is that conventional file-processing environments do not allow needed data to be retrieved in a convenient and efficient manner.
- Atomicity problems: Atomicity of a transaction refers to “All or nothing”, which means either all the operations in a transaction executes or none. For example, a program to transfer $500 from the account balance of Steve to the account balance of Mary. If a system failure occurs during the execution of the program, it is possible that the $500 was removed from the balance of Steve but was not credited to the balance of Mary.
- Data Security: Data should be secured from unauthorized access. For example, a student in a college should not be able to see the payroll details of the teachers, such kind of security constraints are difficult to apply in file processing systems.
I hope guys like these posts and comment on the Purpose of Database Systems.