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| DBMS |
DBMS (Database Management System) is a set of programs used for creating, managing, and operating databases. It is basically used for database operation and manipulations in the data centers. Example: Oracle, SQL Server, My SQL, MS Access.
1. Differentiate between centralized and distributed databases.
Centralized Database System | Distributed Database System |
Data reside in a single location. | The data reside in several locations. |
Files are kept based on the location of disk drives and names. | Files are kept based on names rather than location. |
It does not contain several sites or nodes (i.e., does not contain several computers). | It contains several computers (sites) and communicates with one another through communication media. |
Once the database system fails, it doesn't operate. | If one site fails, the remaining sites may be able to continue operating. |
No risk of data lost | High risk of data theft, hacking, etc. |
Suitable for a single organization like a school, college, industry, etc. of a location. | Suitable for a large organization spread in different geographical locations. |
Low cost | High cost |
2. Explain the advantages of a Database Management System.
Database
A database is the collection of related data. It is the location used for storing data. Example: Student record, accounting record. DBMS is used for creating, managing, and operating databases. It is used for database operation and manipulation of data.
Advantages of Database Management System:
The advantages/pros of a Database management system are:
1. Redundancy can be reduced: The use of DBMS reduces redundancy. Redundancy refers to the duplication of data i.e. data stored in more than one location. The reduced redundancy results in:
- Minimized wastage of storage
- Easier access and manipulation of data
- Confusing cases can be avoided
2. Inconsistency can be avoided: Reduced redundancy results in avoiding inconsistent state. DBMS ensures that the database is always inconsistent state.
3. Standards can be enforced: DBMS applies standards or rules, which are used to minimize errors during the input process and maintain security.
4. Integrity can be maintained: DBMS helps to maintain the accuracy of the data by applying standards or rules.
5. Data can be shared: With the use of DBMS, the same data can be shared and used by multiple users at the same time.
6. Provides security: DBMS provides a security mechanism on the database, so, that it can be used only by authorized users. It provides authentication and access control.
7. Providing a user interface to access data: It provides a user interface through which users can access the database. It provides both GUI and CUI-based user interfaces.
8. Provides facility for backup and recovery: It provides tools for backup restore and recovery tools.
3. What are the roles of DBA? Explain.
Database Administrator
A Database Administrator (DBA) is a person responsible for making strategic and policy decisions regarding data and the database as well as controlling all the operations of the database. DBA provides necessary strategic and technical support for the implementation and control of database operations.
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| Database Administrator |
Roles and Responsibilities of a Database Administrator
The duties and responsibilities of a database administrator are:
1. Defining the internal schema: DBA is responsible for defining how the data is to be represented in the memory. It is the process of designing the physical layer of the database.
2. Defining the external schema: DBA also has the role of designing the logical or conceptual layer of the database. It defines how the data are stored in the tables of the database and how the tables are related to each other.
3. Monitoring the performance of the database: DBA must monitor the performance of the database all the time and take proper action if any problem in the database is detected.
4. Upgrading the database and its server: DBA should upgrade the database and its hardware components if required by the organization or if the requirements are changed.
5. Defining backup and recovery procedures: DBA must define the backup process to be performed repeatedly and must also define the recovery procedure to be followed in case of database crash or system failure.
6. Defining security on the data and the database: DBA is responsible for defining security policies for the protection of data against unauthorized users. DBA also grants access permission to the user according to the responsibility of the user.
7. Learning constantly: DBA must upgrade him/herself constantly regarding new systems about databases, DBMS, security systems, etc.
4. What is data security? Explain.
Data Security
Data security is the method of protecting the data and other resources of a computer system against destruction, unknown, and unauthorized access. It is the process of keeping data protected from corruption, modification by unauthorized users, leakage, and physical harm.
Data security can be maintained at the following levels:
- Physical security: It is concerned with protection from physical damage by keeping data in a safe place and using a proper backup mechanism.
- Logical security: It is concerned with protection from unauthorized access by using proper authentication and users' access control mechanism.
We can implement Data security in the following ways:
- By creating backup copies and storing them in a separate device or separate computer.
- Using a password login system using encryption techniques to prevent unauthorized access
- The system should be located away from the locations where there is a chance of physical damage and disaster (like fire, flood, earthquake, etc.) By keeping the system in a safe place by locking it.
- By using antivirus software to protect from viruses.
- Allowing access to sensitive information only to trusted users.
- Using an access control mechanism, so that data can be accessed only by the permitted users.