Overview of Database Management System Long Answer Type Questions Part 1
Write about the Overview of DBMS.
DBMS is a collection of programs that enables user to create and maintain a database. In other words, it is general-purpose software that provides the users with the processes of defining, constructing and manipulating the database for various applications.
The database management system provides ways to organize, store, retrieve and interact with the data in the database.
Components of Database System:
The database system can be divided into four components
- Users: Users may be of various type such as DB administrator, System developer and End users.
- Database application: Database application may be Personal, Departmental, Enterprise and Internal.
- DBMS: Software that allow users to define, create and manages database access, Ex: MySql, Oracle etc.
- Database: Collection of logical data.
Functions of DBMS:
1. Data Dictionary Management: Data Dictionary Management is one of the most important function in database management system. DBMS stores definitions of the data elements and their relationships (metadata) in a data dictionary. So, all programs that access the data in the database work through the DBMS.
2. Data Storage Management: The DBMS creates and manages the complex structures required for data storage, thus relieving user from the difficult task of defining and programming the physical data characteristics. A modem DBMS system provides storage not only for the data, but also for related data entry forms or screen definitions, report definitions, data validation rules, procedural code, structures to handle video and picture formats, and so on.
3. Data transformation and presentation: The DBMS transforms entered data in to required data structures. The DBMS relieves the chore of making a distinction between the logical data format and the physical data format. That is, the DBMS formats the physically retrieved data to make it conform to the user’s logical expectations.
4. Security Management: Security Management is another important function of DBMS. The DBMS creates a security system that enforces user security and data privacy. Security rules determine which users can access the database, which data items each user can access, and which data operations (read, add, delete, or modify) the user can perform. This is especially important in multiuser database systems.
Advantages of DBMS:
1. Controlling Data Redundancy: If a database have more than one records of same type then it is called data redundancy. In DBMS, all data is stored in one single database file and that recorded data is placed in the database.
2. Data Sharing: Data can be shared by authorized users of the organization among multiple users. Many users can be authorized to access the same data simultaneously. The remote users also can share the same data.
3. Enforcing Data Integrity: In database approach, data integrity is much easier. In database, data is stored in the tables. A single database contains multiple tables which is easy to retrieve and update the data.
4. Data Security: Data security is the protection of the database from unauthorized access. The DBMS ensures access of the database through authorized channel. To ensure security, DBMS provides security such as by giving user name and passwords.
5. Ease of application development: The programmer needs to develop applications according to user specification. The other issues such as data integrity, security etc are handled by DBMS itself which makes application development easier.
Disadvantages of DBMS
1. Cost of Data Conversion: When computer file based system replaced with database system, it must be converted to database file. It’s difficult to convert data file into database, so for this we have to take help of database designers along with application programmers and also we should take help of software which costs lot of money for developing the software.
2. Complexity: Database system creates additional complexity and requirements. DBMS is extremely complex piece of software. The operation of database system with several users and databases is quite costly and demanding.
3. Cost of Hardware and Software: To run DBMS software, we need high speed of data processor and large memory size and DBMS software also too high.
4. Cost of staff training: DBMS is complex database system which is required to train the users all levels including programming, application development etc for which organization has to pay lot of amount for training staff to run the DBMS.
5. Higher impact of failure: In most of organizations, all data stored in a single database. Since all users and applications rely on the availability of the DBMS. If the database is damaged due to electric failure or database corruption data may lost forever.
Define Data, Information, and Database. Explain the differences between the data and information.
Data: Data can be defined as a representation of facts, concepts, or instructions in a formalized manner, which should be suitable for communication, interpretation, or Processing by humans or electronic machines.
Data is represented with the help of characters such as alphabets (A-Z, a-z), digits (0-9) or special characters (+,- ,/,*,<,>,= etc.)
The term data is derived from Latin term ‘datum’ which refers to ‘something given’. The concept of data is connected with scientific research, which is collected by various Organizations, government departments, institutions and non-government agencies for a variety of reasons. There can be two types of data:
1) Primary Data:
- Qualitative Data
- Quantitative Data
2) Secondary Data:
- Internal Data
- External Data
Information: Information is organized or classified data, which has some meaningful values for the receiver. Information is the processed data on which decisions and actions are based.
For the decision to be meaningful, the processed data must qualify for the following characteristics –
- Timely- Information should be available when required.
- Accuracy – Information should be accurate.
- Completeness – Information should be complete.
Information is needed to:
1. To gain knowledge about the surroundings, and whatever is happening in the society and universe.
2. To keep the system up to date.
3. To know about the rules and regulations and bye-laws of society, local government, provincial and central government, associations, clients etc. as ignorance is no bliss.
4. Based on above three, to arrive at a particular decision for planning current and prospective actions in process of forming, running and protecting a process or system.
Database: A collection of data designed to be used by different people is called a database. It is a collection of interrelated data stored together with controlled redundancy to serve one or more applications in an optimal fashion. The data are stored in such a fashion that they are independent of the programs of people using the data. A common and controlled approach is used in adding new data and modifying and retrieving existing data within the database.
Difference between Data and Information
|1. Raw facts gathered about a condition, event, idea, entity or anything else which is bare and random, is called data.||1. Information refers to facts concerning a particular event or subject, which are refined by processing.|
|2. Data are simple text and numbers||2. Information is processed and interpreted data.|
|3. Data is in an unorganized form, i.e. it is randomly collected facts and figures which are processed to draw conclusions.||3. When the data is organised, it becomes information, which presents data in a better way and gives meaning to it.|
|4. Data is based on observations and records, which are stored in computers or simply remembered by a person.||4. Information is considered more reliable than data, as a proper analysis is conducted to convert data into information by the researcher or investigator.|
|5. The data collected by the researcher, may or may not be useful to him, as when the data is gathered, it is not known what they are about or what they represent.||5. Information is valuable and useful to the researcher because it is presented in the given context and so readily available to the researcher for use.|
|6. Data is not always specific to the need of the researcher||6. Information is always specific to his requirements and expectations because all the irrelevant facts and figures are eliminated, during the transformation of data into information.|
|7. Data does not depend upon information||7. Information cannot exist with out data.|
What is a database? Explain the Characteristics of Database.
A collection of data designed to be used by different people is called a database. It is a collection of interrelated data stored together with controlled redundancy to serve one or more applications in an optimal fashion. The data are stored in such a fashion that they are independent of the programs of people using the data. A common and controlled approach is used in adding new data and modifying and retrieving existing data within the database.
Characteristics of Database:
1. It should be able to store all kinds of data that exist in this real world. Since we need to work with all kinds of data and requirements, the database should be strong enough to store all kinds of data that is present around us.
2. It should be able to relate the entities/tables in the database by means of relation, i.e.; any two tables should be related.
3. Data and application should be isolated. Because a database is a system that gives the platform to store the data, and the data is the one that allows the database to work. Hence there should be a clear differentiation between them.
4. There should not be any duplication of data in the database. Data should be stored in such a way that it should not be repeated in multiple tables.
5. DBMS has a strong query language. Once the database is designed, this helps the user to retrieve and manipulate the data. If a particular user wants to see any specific data, he can apply as many filtering conditions that he wants and pull the data that he needs-
6. Multiple users should be able to access the same database, without affecting the other user.
7. It supports multiple views to the user, depending on his role.
8. Database should also provide security, i.e.; when there are multiple users accessing the database, each user will have their own levels of rights to see die database. Some of them will be allowed to see the whole database, and some will have only) partial rights.
9. Database should also support ACID property. i.e.; while performing any transactions like insert, update and delete, the database makes sure that the real purpose of the data is not lost.
Define DBMS. What is the need and Characteristics of DBMS?
DBMS is a collection of programs that enables user to create and maintain a database. In other words, it is general-purpose software that provides the users with the processes of defining, constructing, and manipulating the database for various applications.
The database management system provides ways to organize, store, retrieve and interact with the data in the database. It consists of:
1) A modeling language, used to define the database schema, or structure. Common database structures are hierarchical, network, relational and object-based. Models- differ in how they connect related information. The most widely used, particularly in Web applications, is the relational database model.
2) A database engine that manages the database structure and optimizes the storage of data, whether that is fields, records, files or objects, for a balance between quick retrieval and efficient use of space.
3) A database query language, such as SQL, enables developers to write programs that extract data from the database, present it to the user, and save and store changes.
4) A transaction mechanism that validates data entered against allowed types before storing it, and also ensures multiple users cannot update the same information simultaneously, potentially corrupting the data.
Procedures to provide data in the form required by applications. Applications need not know the physical organization of data –
Need for DBMS: Database systems are basically developed for large amounts of data. When dealing with huge amount of data, there are two things that require optimization: (a)Storage of data and (b) Retrieval of data.
Storage: According to the principles of database systems, the data is stored in such a way that it acquires lot less space as the redundant data (duplicate data) has been removed before storage.
Fast Retrieval of data: Along with storing the data in an optimized and systematic manner, it is also important that we retrieve the data quickly when needed. Database systems ensure that the data is retrieved as quickly as possible.
Characteristics of DBMS:
- It reduces complex relationships between data.
- Enforces user-defined rules and ensures data sharing.
- It provides different interfaces through which user can manipulate the data.
- An integrated database helps in understanding the relationship between data stored in different applications.
- It has automatic backup and recovery procedures.
- Provides a clear and logical view of the process that manipulates data.
- Changes made in the database schema should not affect the other levels.
- Controls data redundancy and control over security.
- It contains ACID properties which stand for Atomicity, Consistency, Isolation, and Durability which maintains data in a healthy state in case of failure.
What is DBMS? What are the Applications of DBMS?
A database is a collection of interrelated data where data can be easily accessed, managed and updated. For example, consider the office department in school maintains details of the student such as the name of the student, age, address, class etc. These all records are related with students stored in a database.
A database management System is a collection of data and set of programs to access the data. It allows creation, definition and manipulation of databases. DBMS provides protection and security to the database. Some examples for popular dbms are MySQL, Oracle, Sybase, Microsoft Access, and IBM DB2.
Applications of DBMS:
- Banking: Banks uses a database for customer accounts, loans and other transactions.
- Airlines: Airlines uses an online database for reservation, arrival and departure of the planes, schedule information etc.
- Education: Schools, colleges and universities use a database for course details Registration, examination details Result etc.
- Credit card transactions: It is used to keep track of purchases on credit cards to generate statements.
- Telecommunications: The telecommunication department uses a database to store information about telephone numbers, details of calls, generating bills etc.
- E-commerce: It uses online databases for buying and selling of products, online transaction processing, internet marketing etc.
- Finance: It uses a database for storing information such as sales, stocks, bonds etc.
- Sales: it uses databases for storing product details, transactions and customer details.
- Human resources: Organizations use databases for storing information about employees, salaries, tax, salary checks etc.