A database is a collection of related data and data is a collection of facts and figures that can be processed to produce information.
Mostly data represents recordable facts. Data aids in producing information, which is based on facts.
Now let us know about the DBMS which stands for the Database management system.
DBMS is software for sorting and retrieving user data by considering appropriate security measures.
It allows users to create their own database and provide an interface between the database.
Characteristics of DBMS
DBMS was a new concept to overcome the deficiencies in the traditional style of data management. DBMS makes complex memory management easy to handle.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.
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.
Less redundancy − 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 attempts of leaving databases in an inconsistent state.
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 a file-processing system was used.
ACID Properties − DBMS follows the concepts of Atomicity, Consistency, Isolation, and Durability (normally shortened as ACID).
Multiuser and Concurrent Access − DBMS supports a multi-user environment and allows them to access and manipulate data in parallel.
Multiple views − DBMS offers multiple views for different users. This feature enables the users to have a concentrated view of the database according to their requirements.
Security − Features like multiple views offer security to some extent where users are unable to access data of other users and departments. DBMS offers many different levels of security features, which enables multiple users to have different views with different features.
Components of DBMS
Data: It is the resource for which DBMS was designed.
Procedure: By using document procedure user has guidance to operate and manage DBMS.
User: Who can access or retrieve the data on demand.
Software: It is the actual DBMS between the physical database and the users of the system. We can say that it creates the data.
Hardware: It is the actual computer system used for keeping and accessing the database.
Classification of DBMS Users
Naive Users: Users who need not to be aware of the presence of the database system or any other system supporting their usage are considering naive users.
Online Users: These are the users who may communicate with the database directly via an online terminal or indirectly via a user interface and application program.
Application Programmers: Who is responsible for developing application programs or user interfaces utilized by the naive and online users fall into this category.
Database Administrator: Centralized control of the database is extended by a person or group of people under the supervision of a high-level administrator. This person or group is referred to as DB.
Facilities provide by the DBMS
Data Definition Language(DDL):
DDL used to define the database structure or schema.
Also used to specify additional properties of the data. The storage structure and access methods used by the database system by a set of statements in a special type of DDL called a data storage and definition language.
Here are some commands that come under DDL:
- CREATE
- ALTER
- DROP
- TRUNCATE
Data Manipulation Language(DML):
DML used to manipulate data in the database is known as DML. It involves retrieval of data from the database, insertion of new data into the database, and the deletion or modification of existing data.
Here are some commands that come under DML:
- INSERT
- UPDATE
- DELETE
Data Control Language(DCL) :
A Data Control Language is a syntax similar to a computer programming language used to control access to data stored in a database (Authorization).
Here are some commands that come under DCL:
- GRANT
- REVOKE
Transaction Control Language(TCL):
TCL used for maintaining consistency of the database and managing transactions in the database
Here are some commands that come under TCL:
- COMMIT
- ROLLBACK
- SAVEPOINT
Data Query Language(DQL)
DQL used to fetch the data from the database.
It uses only one command:
- SELECT
Advantages of DBMS
- Improved Data Sharing: The DBMS help to create an environment in which end user have better access to more and better managed data.
- Data Security: A DBMS provides a framework for better enforcement of data privacy and security policies.
- Decision Making: Better managed data and improved data access make it possible to generate better quality information on which better decisions are based.
- Minimised Data Inconsistency: Inconsistency exists,different versions of same data appears in different places. The probability of data inconsistency minimised in a properly designed database.
- Increase End-User productivity.
Disadvantages of DBMS:
- Increased Cost: Frequently upgrade their product by adding new functionalities DBMS required sophisticated hardware , software and high skilled person. The cost of maintaining all this is very high.
- Management complexity.
- To minimise the efficiency of database , you must keep your system current.
Conclusion
From all of this above experience with an introduction to database management systems, I conclude that DBMS makes complex traditional database handling easier. By just making the tables we can easily handle the things in a few spans of time.
