What is RDBMS ?

RDBMS stands for Relational Database Management System. Also called RDB (Relational Database), it is a database that stores data in tables (rows and columns) so that it can be used to form relations with other tables. The only difference between relational databases and simple databases is that we can easily create relationships with other tables using RDB. Most databases used these days are relational databases.
We can perform any type of operation on RDB, such as updating, deleting, viewing, and so on. Most relational databases use SQL as a language to access the database. SQL (Structured Query Language) is a programming language that is used to communicate with databases. It helps us create, update, or delete data in relational databases. The syntax of SQL is also very simple, making it easy to learn.

Let’s make RDB clear with the help of a simple example. Let's assume we have two tables; one is a student table in which we have student name and student roll number, and the other table is an info table, which has roll number and total marks. So, we can make a relationship between these two tables and find out the total marks of individual students. Note that we have a common column (student roll number) in these two tables. Some of the examples of relational database management systems are mentioned below:-

• MySQL
• Oracle DB
• PostgreSQL
• SQLite
• SQL Server

RDBMS Operation

A relational database management system works in tables; it stores data in the form of tables. There can be any number of tables that contain rows and tables. Every table in database has unique primary key. As we know, tables have rows and columns, so let’s understand the role of these rows and columns. So, a row records the data of an individual entity, and a column holds the data for a specific field. Using SQL, we can run a query to show some specific results. SQL has a term called SQL Constraints. They are used for some rules for data before it enters the table. Let's explore some constraints given below:-

• NOT NULL - It ensures that a column doesn’t have any empty values or NULL values.
• UNIQUE - It ensures that no two values in a given column are the same.
• PRIMARY KEY - A primary key is a group of columns in a table that uniquely identify the row.
• CHECK – This function ensures that columns adhere to any given condition.

Why RDBMS?

The relational database management system is very safe. If for any reason, our programme crashes, our data will remain safe. There are many security layers, so the data will remain safe.
In relational databases, accessing the data is easy and if we want to perform any action like deleting, updating, etc., such a type of action is easy to implement.
A relational database can manage large amounts of data and this data is stored in the form of rows and columns in a table.
Using a foreign key, we can link two or more tables and then work on them according to our requirements.
We can also give permission to multiple users so that they can work individually according to their needs.
Management of relational databases is also very clean and effective as data is stored in the form of rows and columns.

RDBMS Advantages

Below are some of the advantages of relational databases:

1. Relational databases are very flexible in nature. Let's understand this by taking an example. Assume that we have an employee table, and if we need to update any information about an employee, rather than updating it in each file, we simply update it in the main file, and RDBMS automatically updates this information in every file of the database. By doing this, we can save a lot of time.
2. Relational databases can be accessed at any time, and they are also very easy to use. Relational databases allow database admins to control their events, like maintaining data, updating data, etc. Backing up data is also simple with the help of RDBMS and some automation tools.
3. The database admin of a relational database has control over the database and can give specific access to the required user. It cannot give all access to all users. Access is given according to the user’s need.
4. As we know, relational databases use rows and columns to store their data, so tables are very comfortable for users to understand. Also, writing queries for RDBMS is easy.

RDBMS Disadvantages

A relational database has many advantages, but it also comes with some disadvantages. For example, to implement a relational database, we need some special software, so some special software needs to be purchased. This results in an extra cost. Also, to setup a relational database, we have to write millions of lines of code into RDBMS tables. For that, we need some extra programmers. Also, while doing this, we must take care that our data doesn’t fall into the wrong hands. Also, sometimes combining multiple tables can become more complicated in some cases.

Indexing in RDBMS

To get faster access to data, indexes are used. Suppose you have an employee table with 10 employees. If we sort the data in increasing order, we can easily find out the nth salary using indexes.

DBMS vs. RDBMS

Now let's explore the key difference between DBMS and Relational DBMS as given below:

1. In DBMS, only one user is accepted at a time, but in the case of relational databases, multiple users are allowed at a time.
2. Relational databases necessitate greater investment in software and hardware than DBMS.
3. As we know, relational databases make relational between multiple tables, so they can manage large amounts of data easily, but DBMS only manage a small amount of data as compared to RDBMS.
4. A relational database stores its data in the form of tables (using rows and columns), while a DBMS stores its data in hierarchical form.
5. Relational databases support distributed databases (it is a type of database that is present on multiple sites, i.e., on multiple computers or over a network of computers; it is not limited to only one user), while DBMS doesn’t support distributed databases.
6. Relational databases can be normalized, but in the case of DBMS, it is difficult to normalize them.
7. Relational databases follow ACID properties (Atomicity, Consistency, Isolation, Durability) while storing the data, while the DBMS doesn’t follow ACID properties.

For a better understanding of difference between DBMS and RDBMS, refer to Scaler Topics

Author - Arnav Bhardwaj