In this blogpost, we will know about database overview
Database Management System or DBMS in short refers to the technology of storing and retrieving usersí data with utmost efficiency along with appropriate security measures. This tutorial explains the basics of DBMS such as its architecture, data models, data schemas, data independence, E-R model, relation model, relational database design, and storage and file structure and much more.
Why to Learn DBMS?
Traditionally, data was organized in file formats. DBMS was a new concept then, and all the research was done to make it overcome the deficiencies in traditional style of data management. A modern DBMS 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.
Applications of DBMS
Data set is an assortment of related information and information is an assortment of raw numbers that can be handled to create data.
For the most part information addresses recordable realities. Information supports creating data, which depends on realities. For instance, in case we have information about marks got by all understudies, we would then be able to finish up with regards to clinchers and normal imprints.
A data set administration framework stores information so that it becomes simpler to recover, control, and produce data. Following are the significant attributes and uses of DBMS.
ACID Properties − DBMS follows the concepts of Atomicity, 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.
Multiuser and Concurrent Access − DBMS supports multi-user environment and allows them to access and manipulate data in parallel. Though there are restrictions on transactions when users attempt to handle the same data item, but users are always unaware of them.
Multiple views − DBMS offers multiple views for different users. A user who is in the Sales department will have a different view of database than a person working in the Production department. This feature enables the users to have a concentrate 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 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. For example, a user in the Sales department cannot see the data that belongs to the Purchase department. Additionally, it can also be managed how much data of the Sales department should be displayed to the user. Since a DBMS is not saved on the disk as traditional file systems, it is very hard for miscreants to break the code.
Advantage of DBMS
1. Improved data sharing:
The DBMS helps create an environment in which end users have better access to more and better-managed data.
Such access makes it possible for end users to respond quickly to changes in their environment.
2. Improved data security:
The more users access the data, the greater the risks of data security breaches.Corporations invest considerable amounts of time, effort, and money to ensure that corporate data are used properly.
A DBMS provides a framework for better enforcement of data privacy and security policies.
3. Better data integration:
Wider access to well-managed data promotes an integrated view of the organization’s operations and a clearer view of the big picture.
It becomes much easier to see how actions in one segment of the company affect other segments.
4. Minimized data inconsistency:
Data inconsistency exists when different versions of the same data appear in different places.
For example, data inconsistency exists when a company’s sales department stores a sales representative’s name as “Bill Brown” and the company’s personnel department stores that same person’s name as “William G. Brown,” or when the company’s regional sales office shows the price of a product as $45.95 and its national sales office shows the same product’s price as $43.95.
The probability of data inconsistency is greatly reduced in a properly designed database.
5. Improved data access:
The DBMS makes it possible to produce quick answers to ad hoc queries.
From a database perspective, a query is a specific request issued to the DBMS for data manipulation—for example, to read or update the data. Simply put, a query is a question, and an ad hoc query is a spur-of-the-moment question.
The DBMS sends back an answer (called the query result set) to the application.
For example, end users
6. Improved decision making:
Better-managed data and improved data access make it possible to generate better-quality information, on which better decisions are based.
The quality of the information generated depends on the quality of the underlying data.
Data quality is a comprehensive approach to promoting the accuracy, validity, and timeliness of the data. While the DBMS does not guarantee data quality, it provides a framework to facilitate data quality initiatives.
Increased end-user productivity
The availability of data, combined with the tools that transform data into usable information, empowers end users to make quick, informed decisions that can make the difference between success and failure in the global economy.
Disadvantage of DBMS
1. Increased costs:
Database systems require sophisticated hardware and software and highly skilled personnel.
The cost of maintaining the hardware, software, and personnel required to operate and manage a database system can be substantial. Training, licensing, and regulation compliance costs are often overlooked when database systems are implemented.
2. Management complexity:
Database systems interface with many different technologies and have a significant impact on a company’s resources and culture.
The changes introduced by the adoption of a database system must be properly managed to ensure that they help advance the company’s objectives. Given the fact that database systems hold crucial company data that are accessed from multiple sources, security issues must be assessed constantly.
3. Maintaining currency:
To maximize the efficiency of the database system, you must keep your system current.
Therefore, you must perform frequent updates and apply the latest patches and security measures to all components.
Because database technology advances rapidly, personnel training costs tend to be significant. Vendor dependence.
Given the heavy investment in technology and personnel training, companies might be reluctant to change database vendors.
4. Frequent upgrade/replacement cycles:
DBMS vendors frequently upgrade their products by adding new functionality. Such new features often come bundled in new upgrade versions of the software.
Some of these versions require hardware upgrades. Not only do the upgrades themselves cost money, but it also costs money to train database users and administrators to properly use and manage the new features.
Before you begin continuing with this instructional exercise, it is suggested that you have a decent comprehension of fundamental PC ideas like essential memory, auxiliary memory, and information constructions and calculations.