Advantages, Disadvantages And Main Characteristics of Database Approach

Advantages of Database Approach

The database approach has many advantages over the file processing system. Some important advantages of the database approach are as follows:

1. Redundancy control            

          The data in a database appears only once and is not duplicated. For example, the data of a student in the college database is stored in one table. The table can be accessed for different purposes. For example, if we want to store the marks of the students in a table, only Roll No of the student will be used in the second table. The second table will be connected to the student table for accessing the information about the student as follows:

Roll No	Name	Address	Email	Phone
1	Usman	Faisalabad	usman@itseries.com.pk	727253
2	Abdullah	Toronto	Abdullah@itseries.com.pk	784692

 

                                                                   Marks Table

Roll No	Subject	Marks
1	Math	98
1	English	87
2	Math	81
2	English	92

In the above figure, the details of the students are stored in the student table. The Marks table stores only the Roll No of students. The remaining data is not duplicated. Roll No in the Marks table is duplicated for joining two tables.

2. Data Consistency

           An important benefit of controlling redundancy is that the data is consistent. If a data item appears only in one place, it is easy to maintain. It is required to update data, the update is performed in only one place. The change will automatically take effect at all places where ever this data is used.

3. Consistency Constraints

             Consistency constraints are the rules that must be followed to enter data into the database. If the constraints are not fulfilled, data cannot be entered into the database. Database management systems provide an easy way to apply different consistency constraints to ensure data consistency. For example, a constrain can be applied to ensure that the data is always entered in a specific range, etc.

4. Data Atomicity  

A collection of all steps to complete a process is known as a transaction.

Data atomicity means that either a transaction should take place as a whole or it should not take place at all. It ensures that the database will always have correct and consistent data. Suppose a user wants to transfer money from account A to account B. This process consists of two steps:

1. Deduct the money from account A.
2. Add the money to account B.

             Suppose that the system fails when the computer has performed the first step. It means that the amount has been deducted from account A but has not been added to account B. This situation can make data inconsistent. The database management system does not allow such a situation to happen. Database management system either executes both steps or does not execute any step.

5. Data security

               Data security is the protection of the database from unauthorized access. The database management system provides several procedures to maintain data security. The security is maintained by allowing access to the database through the use of a password. Not every use of a database system should be able to access all the data.

                In some situations, it is required to provide different types of access permission to data for different users. For example, a data entry operator should only be allowed to enter data. The chairman of the organization should be able to access or delete the data completely. The database management system provides different levels of security options for different users.

6. Reduced Development Time

             A database organizes data more efficiently than a file processing system. It is often easier and faster to develop programs that use this data many database management systems also provide programs that use this data. Many database management systems also provide several tools to assist in program development. So it reduces the oversell time for developing applications.

7. Compactness

             The database management system stores data with compactness and efficiency. It requires less storage space than the file system. It saves the storage resources of the system and memory is not wasted.

8. Easier Reporting

              Reports are a very important part of database applications. The reports are very essential for taking crucial decisions in an organization. The data in the database is stored in an organized manner. It can easily be retrieved for creating different reports. The reports can be prepared very easily and quickly in the required formal database management system.

9. Data sharing

                Once a database is developed, it can be used by several users in the organization. The database can also be shared by different applications. If a new application requires the same data, it can share the existing database instead of developing it again.

10. Increased Concurrency

                 In some situations, two or more users may access the same file simultaneously. It is possible that the accesses will interfere with each other. This may result in loss of information or even loss of integrity. Many DBMS manage concurrent access and ensure such problems cannot occur.

 11. Improved Backup and Recovery

                In file-based systems, it is the responsibility of the user to protect data from failures of the computer system or application program. This may require taking backup of the data daily. If the data is lost, the backup is restored. The modern DBMS provides facilities to minimize the amount of processing that can be lost due to a failure.

12. Data Independence

                 Database approach provides the facility of data independence. It means that the data and the application program are separate from each other. It is possible to change data storage structures and operations without changing the application programs.

 

Disadvantages of the Database approach

Some disadvantages of using the database approach are as follows:

 

1. High Cost of DBMS

              A complete database management system is very large and sophisticated software. It is expensive to purchase database management software.

2. Higher Hardware Cost

Database management systems are complicated and heavy software. Additional Memory and processing power may be required to run the DBMS, it may require more powerful hardware.           

3. Higher Programming Cost

               DBMS is complex software with many features. The programmers need a thorough knowledge of the system to use it to the best advantage. If the organization hires experienced database programmers, it has to pay extra cost for this expertise.

4. High Conversion cost

               If an organization converts its records to a database, data has to be converted from files to the database system. Because of the different formats used by different systems, it may be a difficult and time-consuming process. Moreover, the structure and data may also have to be modified according to the requirements of DBMS.

5. More Chance of Failure

               In a database management system, all resources and components are centralized. If any of these components fail, the whole system steps.

6. Complexity & performance

                The database management system is general-purpose software. A complete DBMS has to perform many tasks that make it complex and complicated software. In some applications, DBMS may run less efficiently as compared to file processing systems.

 

Difference between File and Database Approach

     The difference between file and database approach is as follows:                    

File-based approach	Database approach
1.The programs and data are interdependent	1.  the programs and data are independent of                   each other
2. The data may be duplicated in different files that cause data redundancy.	2. The data is not duplicated and appears only once.
3. The same data in the different files may be different that creates inconsistency.	3.the data appear only once so it is always consistent
4. The data is separately stored in various files and it is difficult for an application to retrieve the appropriate data.	4. The data is stored in tables that are linked together. The application can retrieve the required data easily
5. The data is distributed in many different files and cannot be shared.	5. The data is stored in one place and can be shared easily.
6. It is difficult to apply data integrity checks on files.	6. database approach provides many constraints for data integrity
7.It provides poor security as the data is widely spread	7. It provides many procedures to maintain data security.
8. It is difficult to maintain as it provides less controlling facilities.	8. It provides many facilities to maintain data security.
9. It is a less complex system.	9. It is a very complex system.
10. The cost is very less than DBMS.	10. The cost is much more than the file system.
11. One application can fail without affecting the others.	11. All applications relying on the database fail I the database fails.

 

• Introduction to Databases