A Database Management System (DBMS) is a set of software that allows you to access, find, and use that data with appropriate security measures in place.
Advantages of (DBMS)
Some important advantages of database management system are as follows:
- Data Independence
- Redundancy control
- Consistency constraints
- Support Complex Data Relationships
- Data Security Features
- Database Backup & Recovery
- Advanced Capabilities
1. Data Independence:
Database approach provides the facility of Data independence. It means that the data and the application programs are separate from each other. The user can change data storage structures and operations without changing the application programs. The user can also modify programs without reorganization of data.
2. Redundancy control:
Redundancy means duplication of data in multiple files. The data in database appears only once. It is not duplicated. The same data is used at all places it is required.
Suppose we want to manage the information of students who study in college and the student who live in hostel. The data of students is stored in college database. If a student also lives in hostel, his record will be stored only in college database. It will not be duplicated.
3. Consistency constraints:
Consistency Constraints are the rules that must be followed to enter data in the database. If a data does not fulfil! these constraints, it cannot be entered in the database.
Database Management Systems provide an easy way for applying different consistency constraints that ensure the consistency of the data in database. For example, a constraint can be applied to ensure that the marks of a student are always between 0 and 100 etc.
4. Support Complex Data Relationships:
Database management system allows the user to design complex data structures. It enables the user to logically view and access data in different ways.
5. Data Security Features:
Data security is the protection of the database from unauthorized access. The database management system provides several procedures to maintain dT security. The security is maintained by allowing access to the database through the use of usernames and passwords. Different users of database system have different levels of access rights to the database.
6. Database Backup & Recovery:
Database management System provides the facility for the backup and recovery. Backup facility is used to store an additional copy of data. The data can be recovered from this file if the original file is lost or damaged. A utility in DBMS is used to recover data. The utility rebuilds the data by using the backup copy of the data.
7. Advanced Capabilities:
DBMS provides advanced access capabilities for online reporting. It uses internet for advanced capabilities.
Disadvantages of (DBMS)
Some important disadvantages of Database Management System (DBMS) are as follows:
- High Cost of DBMS
- Higher Hardware Cost
- Appointing Technical Staff
- Cost of Staff Training
- Problems in Wrong Database Environment
- Need of Data Dictionary
1. High Cost of DBMS:
A complete database management system is very large and complex software. It is expensive to purchase database management system.
2. Higher Hardware Cost:
Database Management System is complicated and heavy software. It requires a large amount of memory and higher processing power to run. It requires powerful hardware to work properly and efficiently.
3. Appointing Technical Staff:
The technical staff such as database administrator and application programmer is required to manage DBMS. The organization needs to pay good salaries to the technical staff.
4. Cost of Staff Training:
DBMS is a complex system and requires trained users to use it properly. The user training is required in all fields such as programming application development and database administrator. An organization may need to spend a lot of amount for staff training.
5. Problems in Wrong Database Environment:
The problems may occur if wrong type of database environment is selected. A database system may also need changes due to change in requirements. The change can be costly due to conversion and testing of the existing programs. It may require a lot of cost to implement the changes.
6. Need of Data Dictionary:
Another disadvantage of DBMS is the need of data dictionary. Data Dictionary stores data definitions or description of the structure of data used in database. It ensure that data is according to the data definition rules. The rules include field names, field size and data types etc. Data dictionary is also used for data access authorization for database users.
Data dictionary is very useful tool but it is also expensive. It requires installation costs as well as hardware requirements.