DATABASE MANAGEMENT SYSTEM

                                              INTRODUCTION to DBMS

Database Management System (DBMS) is a software system that is designed to manage(maintain) and organize(arrange) data in a particular way. It allows users to create and to make modifications in a database as per their queries, as well as maintain the security and access controls for that database.

DBMS is used to store and retrieve(access) the data in coinvent and efficient manner.

Features of DBMS

✴ Minimum Redundancy and Duplication

    Data Redundancy in a database management system (DBMS) refers to the duplication or repetition of data within a database. It occurs when the same piece of data is stored in multiple locations or multiple tables within the database. This redundancy can happen unintentionally or intentionally. But in dbms the these redundancy problems are maximum reduced.

✴ Reduced space and money spend on storage

    All database management systems must save a large amount of data. However, proper data integration saves a lot of space in the database management system. Companies spend a lot of money to keep their data safer. They will save money on data storage and data entry if they have managed data to store.

✴ Data Organization

    File organization refers to the arranging of data in a file (or) a database table. In computer science, file organization is an important concept used in the design and implementation of file systems and database management systems (DBMS). The way how the data is organized or arranged in a file or table can have a significant impact on the efficiency and speed of data access and retrieval. this is all about data organization in DBMS.

✴ Customization of the Database

    Database management tools are essential for IT managers who need to store, access, and manipulate data efficiently and securely. However, not every tool or platform can meet the specific needs and preferences of every organization or project. That's why it's important to know how to customize and extend database management tools to suit your goals and challenges. In this article, you'll learn some of the ways you can tailor and enhance your database management tools using various features, options, and integrations.

✴ Data Retrieval

   In databases, data retrieval is the process of identifying and extracting data from a database, based on a query provided by the user or application.

✴ Usage Of Query Languages

    Query languages, often known as DQLs or Data Query Languages, are computer languages that are used to make various queries in information systems and databases. The Structured Query Language (SQL) is a well-known example. DQL statements are used to query the data contained in schema objects. The primary goal of the DQL Command is to return a schema relation depending on the query supplied to it.

✴ Multi User Access

    A multi-user database system, on the other hand, can be accessed by multiple users simultaneously. It is typically installed on a network server and can be accessed by users who are logged in to the network. Multi-user systems are more complex and require more resources than single-user systems, but they are essential for organizations where multiple users need to access the same data at the same time.

✴ Data Integrity is Maintained

    The importance of data integrity increases as data volumes continue to increase exponentially. Major organizations are becoming more reliant on data integration and the ability to accurately interpret information to predict consumer behavior, assess market activity, and mitigate potential data security risks. This is crucial to data mining, so data scientists can work with the right information.

✴ Management of Metadata

    The term "meta" refers to something that is about itself. The term "data" refers to the actual values that are stored in the database. In today’s data-driven world, data is becoming increasingly valuable for business and organizations. Databases are used to storing and managing the data, and they play a critical role in ensuring that the data is accurate, accessible, and safer.

✴ Maintenance of a Large Database

    Only a database management system can keep large databases of large corporations up to date. These databases necessitate a high level of security as well as backup and recovery capabilities. Database Management System includes all of these functionalities. It has the ability to keep a database with a large amount of data and information.

✴ Data Durability

    Durability in databases is the property that ensures transactions are saved permanently and do not accidentally disappear or get erased, even during a database crash. This is usually achieved by saving all transactions to a non-volatile storage medium.

✴ Provides a High Level of Data Security

    Security of databases refers to the array of controls, tools, and procedures designed to ensure and safeguard confidentiality, integrity, and accessibility. This tutorial will concentrate on confidentiality because it's a component that is most at risk in data security breaches.

✴Conclusion

A lot of software companies and startups ask a variety of questions on Database Management Systems in their interviews and therefore, for people applying for software or data analytics-related job profiles, knowing about Database Management Systems is a must. We hope we have been able to deliver knowledge about the same to our readers through this article.

QUERY IN DBMS

Overview

A Query in DBMS is used to retrival or modification of data stored in the database. In simple words, a query is like a question or a request for any operation on a particular data object. Queries traverse a database and may retrieve data according to the requirements specified. This retrieved data may be displayed in the form of tables ( as in SQL ) or as graphs, pictorials, etc according to the query language used. Queries may also update, delete or add data items in to a database.

✴what is a query ?

A query is a request for data or information from a database table or combination of tables. In the context of queries in a database, it can be either a select query or an action query. A select query is a data retrieval query, while an action query asks for additional operations on the data, such as insertion, updating or deletion. Most formal queries are written in sql(structured query language).

A query can either be a request for data results from your database or for action on the data, or for both. A query can give you an answer to a simple question, perform calculations, combine data from different tables, add, change, or delete data from a database.

What is a Database Query?

DBAs rely on various database query languages to help optimize their systems and ensure the information stored within databases is accessible yet secure; however, Structured Query Language (SQL) is the most popular database query language.

SQL is the standard database language for major RDBMSes, such as Mysql, Oracle, Microsoft Access, SQL server, IBM Db2, and Postgres. It was developed by IBM in the 1970s alongside the Query By Example (QBE) system, which enabled users to input information into a graphical user interface and build queries to search or filter through relational or object-oriented databases based on that information.

How do Queries Work?

The primary purpose of a database query is to retrieve information from a database for the user. This function allows users to access information from the database or change the data in some way, such as adding or deleting information. A database query has several other important functions, including filtering data, presenting results clearly, compiling information and adding criteria. The two common types of database queries are select queries and action queries. Here are the functions of each:

Select query:

A select query retrieves data and allows you to view it. This is the more common type of query. For example, you may use a select query to see a list of employees who work in the accounting and finance departments.

Action query:

An action query allows you to perform a task related to the data. For example, you can use an action query to add new employees to a database of existing staff. Here are some common types of action queries:

• Update query: This allows you to change a set of data in existing tables within the database.
• Append query: With this, you can add a set of data to existing tables within the database.
• Make-table query: This allows you to create a new table in the database using data from other tables.
• Delete query: This allows you to delete a set of data from tables in the database. A delete query is a permanent action, so it's a good idea to create a backup of your files when using it.
•    This is a small overview about what is query and what        does it do...........

DBMS vs RDBMS: Difference between DBMS and RDBMS

 The below table demonstrates the main difference between RDBMS and DBMS:

                                                          Difference between DBMS and RDBMS

Parameter	DBMS	RDBMS
Storage	DBMS stores data as a file.	Data is stored in the form of tables.
Database structure	DBMS system, stores data in either a navigational or hierarchical form.	RDBMS uses a tabular structure where the headers are the column names, and the rows contain corresponding values
Number of Users	DBMS supports single user only.	It supports multiple users.
ACID	In a regular database, the data may not be stored following the ACID model. This can develop inconsistencies in the database.	Relational databases are harder to construct, but they are consistent and well structured. They obey ACID (Atomicity, Consistency, Isolation, Durability).
Type of program	It is the program for managing the databases on the computer networks and the system hard disks.	It is the database systems which are used for maintaining the relationships among the tables.
Hardware and software needs.	Low software and hardware needs.	Higher hardware and software need.
Integrity constraints	DBMS does not support the integrity constants. The integrity constants are not imposed at the file level.	RDBMS supports the integrity constraints at the schema level. Values beyond a defined range cannot be stored into the particular RDMS column.
Normalization	DBMS does not support Normalization	RDBMS can be Normalized.
Distributed Databases	DBMS does not support distributed database.	RBMS offers support for distributed databases.
Ideally suited for	DBMS system mainly deals with small quantity of data.	RDMS is designed to handle a large amount of data.
Dr. E.F. Codd Rules	Dbms satisfy less than seven of Dr. E.F. Codd Rules	Dbms satisfy 8 to 10 Dr. E.F. Codd Rules
Client Server	DBMS does not support client-server architecture	RDBMS supports client-server architecture.
Data Fetching	Data fetching is slower for the complex and large amount of data.	Data fetching is rapid because of its relational approach.
Data Redundancy	Data redundancy is common in this model.	Keys and indexes do not allow Data redundancy.
Data Relationship	No relationship between data	Data is stored in the form of tables which are related to each other with the help of foreign keys.
Security	There is no security.	Multiple levels of security. Log files are created at OS, Command, and object level.
Data Access	Data elements need to access individually.	Data can be easily accessed using SQL query. Multiple data elements can be accessed at the same time.
Examples	Examples of DBMS are a file system, XML, Windows Registry, etc.	Example of RDBMS is My Sql, Oracle, SQL Server, etc.