Relational Database Management Systems (RDBMS): All You Need to Know

By |2021-06-28T14:01:52+00:00January 1st, 2020|

A Relational Database Management System (RDBMS) provides a foundation for numerous apps and services. Technologically, RDBMS are considered primeval. However, the strong theoretical foundation of this technology has kept it pertinent in a volatile industry. This is why even non-relational databases include RDBMS-like features, such as the SQL interface in Hadoop.

Before we begin, it is important to understand what is a database management system; then, we’ll cover what an RDBMS is, the features of a relational database and how it works. Next, we’ll see how it is different from a DBMS. Lastly, we’ll look at some of the key advantages of relational RDBMS.

What is a Database Management System?

A database management system (DBMS) is software designed to store, retrieve, and manage data in databases. The most prevalent DBMS system is the RDBMS. The full form of RDBMS is Relational Database Management System.  Now that it is clear what a database management system is, let’s learn about the relational database management solution.

relational database management system

What is Relational Database Management System with Example?

According to E. F. Codd’s relational model, an RDBMS allows users to construct, update, manage, and interact with a relational database, storing data in a tabular form. Therefore, consider RDBMS as an advanced data management system that makes gaining insights from data a lot easier. But why do we need a relational database?

Today, various businesses use relational database architecture instead of flat files or hierarchical databases for their company database management system (DBMS).  So, what is the reason for creating a relational database?  A relational database is purpose-built to handle a wide range of data formats and process queries efficiently. And how is data in a relational database system organized? The answer to this is simple; a relational database system organizes data in tables that can be linked internally depending on common data. This allows the user to retrieve one or more tables easily with just one query. On the other hand, flat-file stores data in a single table structure, making it less efficient, consuming more space and memory which is why we need a relational database. An example of a relational database management system could be a production department in an organization that leverages this model to process purchases and track inventory.

The most commercially available and company-wide database management system or relational management system in use today is Structured Query Language (SQL) to access the database. Other widely used relational database management systems for companies include Oracle, MySQL, PostgreSQL, and Microsoft SQL Server. RDBMS structures are most commonly used to perform CRUD (create, read, update and delete) operations, which are critical in supporting consistent data management. Now that you know the definition of a RDBMS let’s look at how it is different to a DBMS along with the characteristics of a relational database system.

Differences Between RDBMS and DBMS

There are some contrasting differences between RDBMS vs. DBMS. An RDBMS is an advanced version of a DBMS. Unlike a DBMS that manages databases present on the computer network and hard disks, an RDBMS database helps maintain the relationships between its tables.

The following are some of the main differences between an RDBMS and a DBMS:

  • The number of operators: A DBMS allows only a single operator at a time, whereas multiple users can operate an RDBMS concurrently. This is because an RDBMS uses intricate algorithms that enable several users to simultaneously access the database while preserving data integrity.
  • Hardware and software needs: A DBMS utilizes fewer resources for data storage and retrieval as compared to an RDBMS. This is because the latter is more complex due to its multi-table structure and cross-referencing capability, making it costlier than a DBMS. RDBMSs are also generally used for enterprise-class applications, while DBMSs are more commonly utilized for smaller, purpose-specific applications.
  • Data modification: Altering data in a DBMS is quite difficult, whereas you can easily modify data in an RDBMS using an SQL query. Thus, programmers can change/access multiple data elements simultaneously. This is one of the reasons why an RDBMS is more efficient than a DBMS.
  • Data volume: A DBMS is more suitable for handling low data volume, whereas an RDBMS can handle even large data volumes.
  • Keys and Indexes: A DBMS doesn’t involve keys and indexes, whereas an RDBMS specifies a relationship between data elements via keys and indexes.
  • Data consistency: As a DBMS does not follow the ACID (Atomicity, Consistency, Isolation, and Durability) model, the data stored can have inconsistencies. Whereas an RDBMS follows the ACID model, which makes it structured and consistent.
  • Database structure: A DBMS works by storing data in a hierarchical structure, while an RDBMS stores data in tables.
  • Data fetching speed: In a DBMS, the data fetching process is quite slow, especially when data is complex and large. This is because each of the data elements must be fetched individually. In an RDBMS, data is fetched at a faster pace because of the relational approach. Plus, SQL facilitates quicker data retrieval in an RDBMS.
  • Distributed databases: A DBMS doesn’t support distributed databases, whereas an RDBMS offers full support for distributed databases.
  • Client-server architecture: Unlike a DBMS, an RDBMS supports client-server architecture.

How Does an RDBMS Work?

A Relational database data structure works by using multiple tables, and every table is arranged into rows (also called records or tuples) and columns (also known as fields or attributes).

Tables in the relational database can be connected in different ways, such as:

  • A record in one table could be related to another record in a different table (1:1 relationship)
  • A record in one table may be related to several records in other tables (1:M relationship)
  • Several table records could be linked to multiple records in a different table (M:N relationship)

However, before tables are created, a relational database management system must ensure that:

  • Each table has a unique primary key, which has no null values.
  • The foreign key, which is used to relate to 2 tables, is preserved in one table and refers to the primary key of another table.
  • No column has a null value (empty cell).

Here’s an example of what is a table in a relational database:

relational database management system

Relational database table example. Source: Guru99

An RDBMS usually comes with data dictionaries and collections of metadata, which are beneficial in data management. A data dictionary defines the data objects of every user within the database. As a result, it helps users identify all the objects which exist in the database as well as who can access them.

For instance, it’s humanly impossible to remember all the tables stored in a huge database. Now, if you want to search for a specific table, such as Products, you can use a data dictionary to look up all the tables named Products. Then, from the list of resulting tables, you can identify your required one.

Advantages of RDBMS

The pros of a relational database management system offer a methodical view of data, which helps businesses improve their decision-making processes by enhancing different areas.

Various other benefits of relational database software are:

Enhanced Data Security

The authorization and access control features in an RDBMS support advanced encryption and decryption, enabling database administrators to manage access to the stored data. This offers significant benefits in terms of security. In addition, operators can modify access to the database tables and even limit the available data to others. This makes RDBMSs an ideal data storage solution for businesses where the higher management needs to control data access for workers and clients.

Retain Data Consistency

In an RDBMS, it is easier to add new data or modify existing tables while maintaining data consistency with the existing format. This is mainly because an RDBMS is ACID-compliant.

Better Flexibility and Scalability

An RDBMS offers more flexibility when updating data as the modifications only have to be made once. For instance, updating the details in the main table will automatically update the relevant files and save you the trouble of changing several files one by one. Plus, each table can be altered independently without disturbing the others. This makes relational databases scalable for growing data volumes.

Easy Maintenance

Relational databases are considered low-maintenance because users can quickly test, regulate, fix and back up data as the automation tool in RDBMS help systematizes these tasks.

Reduced Risk of Errors

In relational database software, you can easily check for errors against the data in different records. Furthermore, as each data item is stored at a single location, there’s no possibility of older versions blurring the picture.


Over time, RDBMSs have evolved to provide increasingly advanced levels of query optimization and sophisticated plugins for enterprise developers. As a result, these relational database management systems have become essential for a variety of enterprise applications. They also serve as a focal point in numerous applications, such as reporting, analytics, and data warehousing.