What is Database Management System ? DBMS Interview Questions
What is Database ?
Database is a collection of related data that is organized in such a way that it can easily be accessed, managed and updated.
Most Databases contain many tables, each of which can contain many different fields.
For example, a company’s database may include tables for products, employees, and financial records. Each of these tables has different fields, which are related to store information in the table.
What is Database : Video
What is Database Management System ? DBMS Interview Questions
Operations Perform on Database
These are various operations which are performed on database –
- Insertion
- Updation
- Deletion
- Retrive
- Sorting
What is Database Management System ?
DBMS stands for the “Database Management System”. Database management system is a software program that manipulates digital data using the computer, make it up-date, edit it, share the data, delete the old data, and Works to store new data.
Using the Database management system computer, the system is used to store the facts in one place and use them by authorized users. Data Base Management System (DBMS) provides the facility to share data and information for multiple purposes to authorized users.
DBMS Softwares
These are various Database Management System softwares –
- Oracle Database Software
- Microsoft SQL Server
- Microsoft Access.
Users of Database Management System
These are mainly three types of users in Database Management System (DBMS) –
- Designer – These are people who design DBMS. They use DBMS after several reasons, such as to test or to modify DBMS.
- Admin – Administrator is the person who controls DBMS. Administrator gives access control to all users and if there is a problem in DBMS, then the Administrator handles it.
- User – User is the person who performs operations on data such as insert, update, and delete etc.
Types of Database Management Systems
There are mainly four types of Database Management System –
- Hierarchical DBMS
- Network DBMS
- Relational DBMS
- Object Oriented DBMS
Every type of DBMS database is structured separately and on the basis of which it has been categorized. These are being described below.
- Hierarchical DBMS
Hierarchical DBMS was introduced in IBM in 1968. When a data item in a DBMS database is presented like a sub unit of another data item, or when there is a child / parent relationship between data items in a database of DBMS, it is called hierarchical DBMS.
Direct relations are only in those data items that are stored together. Data items in this type of DBMS are present / stored in the form of tree structure.
- Network DBMS
When there is many to many relationship between data items in a database of DBMS, then it is called network DBMS. Because there are many to many relationships between data, so network DBMS is very complicated.
- Relational DBMS
When there is a form of database relationship tables in a DBMS, then it is called relational DBMS. In this type of DBMS, the data is stored in the combination of row (tuples) and columns (attributes).
In such a DBMS, there is an unique in every table, which uniquely identifies all the data items. This type of database is very easy to use.
- Object Oriented DBMS
Object oriented DBMS provides database programming capability to you. In this type of DBMS object oriented programming languages add database functionality. Such DBMS is handled directly by programming language.
Advantages Of Database Management System
The database management system has both advantages and disadvantages.
Let’s first see what is the benefits of DBMS after which the loss is given below.
- Reduction in Data Repitition – There is no duplication of data normally in a properly organized database. Due to keeping all the data in one place, every information is stored only once.
- Data Consistency – Due to being focused on the same data of data, Data Stability is maintained as it eliminates the possibility of two of the same information. Data Variable occurs when the data is placed in two places and only one place is rectified.
- Data Sharing – By sharing data, you can use Program Data at one time. In which programs do not need to prepare their own database and it saves a lot of time and effort.
- Security Of Data – Data Security This system protects data from the Unauthorized Users and Illegal Changes for the Database Management System. That is, it only permits Authorized Users to use Data.
- Data Integrity – Overall Completeness, Accuracy and Consistency (Continuity) refers to the lack of change between two updates of a data record. Data Integrity shows that the database stores. The data is absolutely correct and new.
This is the main 5 benefits of the Database Management System.
Disadvantages Of Database Management System
- Complexity – Improving the ability to do a good job of a database management system makes DBMS software difficult. Failure to understand database management system can cause serious consequences for an organization.
- Cost of Staff Training – The maximum Best Database Software and Simple Database Software are extremely complex for the system, so the user reads the need to provide training to use the database. In order to run DBMS Software, the organization has to pay a large sum to the Employees for training.
- Appointing Technical Staff – In an organization, Trained Technical Staff such as Database Administrator, Application Programmer etc. are required, for which the organization has to pay a good salary to these individuals, which increases the Database Management System Software’s Cost.
- Database Failure – In many organizations, all the data is stored in the same database. If the power is closed due to If the database fails or Database Storage Device fails, then all of our Valuable Data Loss can be lost or the entire system may be shut down.
- Effort to transfer data – To transfer data from the existing system to the database, there may be a lot of difficulties and it can take a lot of time.
Components of DBMS
These are mainly four components of Database Management System –
- User: – In DBMS the user is divided into three types.
- Application programmer: – This is software developer which creates the application of a database.
- DBA (Database Administrator): – This is responsible for the design and maintenance of the database.
- End user: – This accesses the database. Access to the database is done by a terminal. And the query language provided by the database system Access is done through.
- Software: – Software is the actual DBMS between the physical structure database and the uses of the system. All the request from the user for accessing the database are handled by Database Management System.
- Hardware: – The hardware is the actual computer system used for keeping and accessing the database. Conventional DBMS hardware consists of secondary storage devices such as harddisk.
- Data: – Data can be placed in numerical, alphabetic or graphics format.
Characteristics of Database Management System
The Database Management System has the following characteristics −
- Real-world entity − A modern DBMS is more realistic and uses real-world entities to design its architecture. It uses the behavior and attributes too. For example, a school database may use students as an entity and their age as an attribute.
- Relation-based tables − DBMS allows entities and relations among them to form tables. A user can understand the architecture of a database just by looking at the table names.
- Isolation of data and application − A database system is entirely different than its data. A database is an active entity, whereas data is said to be passive, on which the database works and organizes. DBMS also stores metadata, which is data about data, to ease its own process.
- Less redundancy − DBMS follows the rules of normalization, which splits a relation when any of its attributes is having redundancy in values. Normalization is a mathematically rich and scientific process that reduces data redundancy.
- Consistency − Consistency is a state where every relation in a database remains consistent. There exist methods and techniques, which can detect attempt of leaving database in inconsistent state. A DBMS can provide greater consistency as compared to earlier forms of data storing applications like file processing systems.
- Query Language − DBMS is equipped with query language, which makes it more efficient to retrieve and manipulate data. A user can apply as many and as different filtering options as required to retrieve a set of data. Traditionally it was not possible where file-processing system was used.
- ACID Properties − DBMS follows the concepts ofAtomicity, Consistency, Isolation, and Durability (normally shortened as ACID). These concepts are applied on transactions, which manipulate data in a database. ACID properties help the database stay healthy in multi-transactional environments and in case of failure.
- Security − Features like multiple views offer security to some extent where users are unable to access data of other users and departments. DBMS offers methods to impose constraints while entering data into the database and retrieving the same at a later stage. DBMS offers many different levels of security features, which enables multiple users to have different views with different features.
Functions of DBMS
The functions of a DataBase Management System may be summarized as follows:-
- DBMS stores the definitions of data and their relationships (metadata) in a data dictionary; any changes made are automatically recorded in the data dictionary.
- The DBMS creates the complex structures required for data storage.
- Database Management System creates a security system and enforces security within that system.
- The DBMS creates complex structures that allow multiple-user access to the data.
- DBMS performs backup and data recovery procedures to ensure data safety.
- Database Management System promotes and enforces integrity rules to eliminate data integrity problems.
- DBMS provides access to the data via utility programs and from programming languages interfaces.
- The DBMS provides end-user access to data within a computer network environment.
DBMS Interview Questions
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