RDBMS - Relational Database Management System

What is an RDBMS?

RDBMS stands for relational database management system—a software system that enables you to define, create, maintain, and control access to relational databases. It is the underlying part of the interface layer that helps you store and work with data.

To fully understand how RDBMS works, let’s first address what makes relational databases unique and why they are the most popular in modern database applications.

Relational databases are designed to store data in structured tables made up of rows and columns. This approach creates relationships between the tables and allows data points to be connected and queried with ease. At the core of a relational database is SQL (Structured Query Language)—a flexible, intuitive language that lets you create, manage, and manipulate data efficiently.

Types of RDBMS systems

RDBMS solutions come in different forms, depending on how they are deployed and used. The main types include:

Client-server RDBMS

In this model, the database runs on a central server, and multiple clients (applications or users) connect to it.

  • Example: Microsoft SQL Server or Oracle Database in a corporate network.
  • Use case: Enterprise systems where many users need concurrent access to shared data.

Cloud-based RDBMS

Hosted on cloud platforms, these systems provide scalability and flexibility without heavy on-premises hardware investments.

  • Example: Amazon RDS for MySQL, Google Cloud SQL, or Azure SQL Database.
  • Use case: Web applications that require on-demand scaling and global accessibility.

Embedded RDBMS

With this approach, lightweight databases are integrated directly into applications, often running locally on a device.

  • Example: SQLite in mobile apps, point-of-sale software, or IoT devices.
  • Use case: Applications that need a self-contained database without a separate server.

RDBMS vs DBMS: Key differences

What makes an RDBMS (Relational Database Management System) different from a DBMS (Database Management System)?

The main difference between a DBMS and an RDBMS lies in how data is organized and managed. A DBMS like Microsoft Access stores data as files or collections of records without strict relationships, making it suitable for small-scale applications. In contrast, an RDBMS like MySQL organizes data into structured tables with rows and columns, enforces relationships through keys (primary and foreign), and supports complex queries using SQL.

RDBMS solutions also offer higher scalability, data integrity, and security, which is why they dominate modern enterprise and web applications, while traditional DBMS tools are now mostly used for simpler or desktop-based systems.

Examples of RDBMS in action

Below are a few examples of relational databases and the real-world scenarios where they excel.

  • Oracle Database: Widely used in banking systems to handle secure transactions and customer records.
  • MySQL: Powers many e-commerce platforms, such as online stores running on Magento or WordPress (WooCommerce).
  • Microsoft SQL Server: Often found in corporate HR and payroll systems, where reliability and integration with Microsoft tools matter.
  • PostgreSQL: Popular for geospatial applications and data analytics platforms, thanks to its advanced features and extensibility.
  • IBM Db2: A backbone for insurance and financial institutions, managing large volumes of client data and claims.
  • MariaDB: Adopted by startups and SaaS applications, offering scalability without licensing costs.
  • SQLite: Embedded in mobile apps (like messaging and note-taking apps) for lightweight, local data storage.
Work model

How does the relational model work?

Like we mentioned above, RDBMS stores data in tables. Each row in a table is a record with a unique ID, which is called primary key. The columns of a table contain attributes of the data. Since each record typically has a value for each attribute, it becomes easy to form flexible relationships between data points.

Let's take a look at the basic notions associated with relational databases.

Primary key is a unique ID that identifies each row of a table.

Foreign key is a field (or multiple fields) in one table that refers to a primary key in another table. It helps establish relations between tables.

View is a virtual table that does not store data; instead, it presents a certain data output that is computed from underlying tables.

Index is a data structure that contains a copy of a column (or multiple columns) from a database table that is ordered to accelerate database retrieval operations on the original column.

Structured Query Language (SQL) is a domain-specific language used for storing, retrieving, and manipulating data—a standard for relational databases.

SQL query is a request for information from an RDBMS. Users write and execute queries to retrieve, add, modify, and delete data from relational databases.

Types of relationships in RDBMS

There are three main types of relationships between tables that ensure the absolute flexibility of the relational database model.

One-to-one relationships

One-to-one relationship is when a single record in table A is related to one (and only one) record in table B.

One-to-one relationships

One-to-many relationships

One-to-many relationship is a bit more complex: a single record in table A is related to multiple records in table B.

One-to-many relationships

Many-to-many relationships

Finally, the most sophisticated example is many-to-many relationship, when multiple records in table A are related to multiple records in table B.

Many-to-many relationships

Relational notations

Now that we have described the main types of relationships, we can add a few words on how they are represented on entity-relationship diagrams through relational notations.

IDEF1X notation

IDEF1X stands for integrated definition for data modeling. Diagrams of this type show entities connected to each other without relationship symbols. The attributes for any entity are listed as part of a table inside each entity shape instead of separate symbols.

IE notation

IE notation (also known as crow's foot notation) uses graphical symbols to show the 'many' side of relationships.

Parent record Child record Example
1 (exactly one) 0..N (zero, one, or more) Notation example 1
1 (exactly one) 0..1 (zero or one) Notation example 2
0..1 (zero or one) 0..N (zero, one, or more) Notation example 3
Data 0..1 (zero or one) 0..1 (zero or one) Notation example 4

Key features of RDBMS

Structured and interrelated data

Structured and interrelated data

Data in relational databases is stored in a well-structured and easily understandable table format. Meanwhile, versatile relations between tables and the use of SQL to write queries of different complexity contribute to the flexibility of data management.

ACID support

ACID support

ACID (which comprises Atomicity, Consistency, Isolation, Durability) is a well-known set of properties of database transactions meant to guarantee data validity despite errors, failures, and other possible mishaps. Relational databases deliver full ACID support.

Multi-user access

Multi-user access

Relational databases provide multi-user access, along with privileges that allow database administrators to have complete control over database activities and grant different levels of access to other users.

Ease of use

Ease of use

Besides the overall convenience of storing, accessing, and managing data in tables, we should mention a multitude of database tools that offer intuitive GUIs and make daily development and administration of databases relatively easy, even for newcomers.

Advantages and disadvantages of RDBMS

The vast capabilities and benefits of relational database management systems make them perfect for modern software solutions. But despite their usefulness, they come with costs and complexities. Here are the advantages and disadvantages of RDBMS.

The pros:
  • Organized and flexible data management: In an RDBMS, data is stored in structured tables with relationships, making it easy to update, search, or extend (for example, adding a new “Orders” table in an e-commerce site).
  • Data integrity and security: RDBMS also includes constraints, keys, and role-based access to keep information accurate and safe, which is essential in banking systems.
  • Backup and recovery support: The RDBMS built-in tools protect against data loss, ensuring business continuity in critical services like airline booking systems.
  • Regulatory compliance: The advanced auditing and encryption features in an RDBMS help organizations meet standards such as GDPR or HIPAA.
  • Integration with enterprise software: RDBMS works seamlessly with ERP, CRM, and analytics tools, accelerating development in corporate IT environments.
The cons:
  • High cost: Enterprise licenses (Oracle, SQL Server) and the hardware they require can be expensive for organizations.
  • Scaling challenges: Handling vast datasets or high traffic often requires costly clustering or cloud solutions.
  • Maintenance overhead: Frequent updates, tuning, and patching are necessary to maintain strong performance and security.
  • Need for expertise: Designing and managing relational databases requires trained administrators and developers, which adds to staffing costs.

What are the most popular relational databases in 2026?

RDBMS proved to be the optimal choice for data management in software solutions from nearly every business domain. Examples of the most popular relational database management systems include Oracle, MySQL, Microsoft SQL Server, PostgreSQL, SQLite, and MariaDB. To explore which system suits you best, refer to the Comparing the Best Database Management Systems article, which provides a detailed comparison of different types of RDBMS.

For each of these, there is a variety of database tools that help tackle routine development and administration tasks with ease and convenience.

  • MySQL
  • SQL Server
  • PostgreSQL
  • SQLite
  • MariaDB

Oracle Database

Oracle Database is renowned for its overall complexity, rather difficult management, and high costs. However, in exchange it offers high portability and backward compatibility, easy recovery, and excellent performance.

Oracle

MySQL

MySQL is one of the leading relational database management systems that boasts a huge community. Although MySQL is generally a free and open-source RDBMS, it is also available under a variety of proprietary licenses.

MySQL

SQL Server

SQL Server is pretty much the world's most advanced commercial RDBMS, developed by Microsoft and perfectly tailored to corporate IT environments. It delivers secure and efficient data storage and an infrastructure with multiple additional services.

SQL Server

PostgreSQL

PostgreSQL is an open-source RDBMS that offers rich functionality, support for a wide variety of data types, and storage of schemaless data. The popularity of PostgreSQL is currently on the rise.

PostgreSQL

SQLite

SQLite is a fast and compact database engine; not a full-fledged piece of software, but rather a library that can be embedded in applications.

SQLite

MariaDB

MariaDB is a community-developed and commercially supported fork of MySQL that was designed to get improved performance and stability as well as adhere to the open-source policy. It is worth noting that MariaDB remains a capable drop-in replacement for MySQL.

MariaDB

How to choose the right relational database?

Commercial databases

  • High licensing costs
  • On-demand tech support
  • Regular updates supplied by the vendor
  • Reasonable for commercial software
Microsoft SQL Server
Microsoft SQL Server
IBM DB2
IBM DB2
Oracle Database
Oracle Database

Open-source databases

  • Open-source licensing
  • No official support
  • Large user communities
  • For commercial and non-profit software
MySQL
MySQL
MariaDB
MariaDB
SQLite
SQLite
PostgreSQL
PostgreSQL

dbForge Studio: Best tools to work with RDBMS

  • Database development
  • Testing
  • Data loading
  • Data analysis
  • Maintenance
Database design

Database design

You can easily create and manage tables in a visual editor and draw database structures on entity-relationship diagrams.

  • Drag-and-drop database objects from Database Explorer directly to your diagram
  • View logical relationships between tables
  • Create and edit columns, indexes, primary and foreign keys, check constraints, statistics, triggers, and table storage properties
  • Add and modify database files, set up database options, handle filegroups, and view database DDL
  • Reverse-engineer SQL databases
Available in
free
free
free
free
Database development

Database development

You can speed up daily SQL coding and improve your performance with coding assistance and change management tools.

  • Code up to 2-4 times faster with smart SQL code completion and a collection of code snippets
  • Unify your corporate coding standards with a rich selection of formatting options
  • Use smart refactoring with auto-correction of references to renamed objects
  • Compare database schemas and deploy changes across different environments
  • Handle changes in multiple version control systems
  • Debug stored procedures, triggers, and functions
  • Generate full database documentation in several formats
Available in
dbForge Studio
for SQL Server
dbForge Studio
for MySQL
dbForge Studio
for Oracle
dbForge Studio
for PostgreSQL
free
free
free
free
Database testing

Testing

The Studios deliver 200+ generators of realistic test data and handy tools to set up automated unit testing.

  • Generate any volumes of meaningful test data to populate your SQL databases with
  • Maintain database integrity and data consistency
  • Keep code quality at an all-time high with unit testing
  • Identify performance bottlenecks and optimize your SQL queries via query profiling
  • Schedule routine tasks for execution from the command line
Available in
dbForge Studio
for SQL Server
dbForge Studio
for MySQL
dbForge Studio
for Oracle
dbForge Studio
for PostgreSQL
free
free
free
free
Data loading

Data loading

With our tools, the most versatile data loading and management tools are always at your service.

  • Import and export data from/to 10+ file formats
  • Edit your data visually
  • Compare table data, analyze differences, and generate reports
  • Sync table data between source and target databases
  • Customize and save templates for recurring tasks
  • Automate your daily operations from the command line
Available in
dbForge Studio
for SQL Server
dbForge Studio
for MySQL
dbForge Studio
for Oracle
dbForge Studio
for PostgreSQL
free
free
free
free
Data analysis

Data analysis

The Studios help you effectively retrieve actionable insights for your business using the integrated tools that facilitate data analysis and reporting.

  • Use master-detail data browsing
  • Aggregate data in visual pivot tables
  • Create comprehensive data reports
Available in
dbForge Studio
for SQL Server
dbForge Studio
for MySQL
dbForge Studio
for Oracle
dbForge Studio
for PostgreSQL
free
free
free
free
Database maintenance

Administration and maintenance

Finally, you can effortlessly streamline routine database administration with a set of specialized tools.

  • Manage user accounts, roles, and permissions
  • Monitor server performance and eliminate performance bottlenecks in a matter of moments
  • Back up and restore your databases
  • Manage and analyze trace results
  • Find invalid objects across multiple databases
  • Optimize tables
Available in
dbForge Studio
for SQL Server
dbForge Studio
for MySQL
free
free
free

Need an all-in-one solution to manage your RDBMS?

Get the most advanced development and administration toolkits
for MySQL, MariaDB, SQL Server, Oracle, and PostgreSQL databases
Learn more