Relational Database Management Systems (RDBMS) are the most widely used database management systems in the world. They have been instrumental in the development of modern computing and data management.
An RDBMS uses a relational model to organize and manipulate data. This model represents data as sets of interrelated tables or relations, with each relation consisting of rows (tuples) and columns (attributes). The relational model offers several advantages, including the ability to efficiently store and retrieve large amounts of data, enforce data integrity and consistency, and support powerful querying and reporting capabilities.
In this article, we will provide an introduction, covering the key concepts and components of this type of database system. Whether you’re a database administrator, a developer, or simply interested in learning more about databases, this article will provide you with a solid foundation in RDBMS.
Examples of Relational Database Management Systems
Just to name a few,
- Oracle
- PostgreSQL
- MySQL
- Microsoft SQL Server
- SQLite
are Relational Database Management Systems. With their help, you can create, host, and manage your databases.
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The table below briefly describes each of these RDBMS and gives some information about the first and the latest releases. I also provided a few latest features so you could get an idea of what challenges the creators are working on.
| Logo | License | Description | Releases | Latest Features |
 | Production and Test environments: Oracle Master Agreement (OMA) or Oracle License and Services Agreement (OLSA) Development Environment: OTN (free, limited license) | Multi-model database management system produced by Oracle Corporation | OracleV2 in 1979 -> Oracle Database 21C, 2021 | Automatic Materialized Views, Binary JSON Data Type, Blockchain Tables, Sharding advisor tool, SQL macros, and others |
 | PostgreSQL License (similar to BSD or MIT licenses) | Free, open-source system implemented as a post-Ingres project by Michael Stonebraker | PostgreSQL 6.0, 1997 -> PostgreSQL 15.1, 2022 | SQL-standard MERGE statement supports Python 3 |
 | Proprietary editions: Enterprise Standard Web Free editions: Express Developer | Proprietary, implemented by Microsoft | SQL Server 1.0, 1989 -> SQL Server 2022 | Azure Active Directory authentication, Multi-Write Replication, Contained Availability Groups, Query Store Enhancements |
 | GPL | Free, open-source. The name comes from a combination of “My” the name of co-founder Michal Widenius’s daughter My and “SQL” | MySQL 5.1, 2008 -> MySQL 8.0, 2022 | – InnoDB, Optimizer, JSON enhancements – Table encryption management- |
 | Public domain, a license is not required | Belongs to a family of embedded databases. It means the RDBMS is not a standalone app but a small library of 700 KiB that you can embed to your apps. | SQLite 1.0, 2000 -> SQLite 3.40.0 2022 | – Full-text searches on documents – Support creating tables without rowid |
What are relational databases?
Relational databases store their data in tables formed by rows and columns. The place where a row crosses a column is called a field.
Each table represents some entity from the real world. For example, a University database can contain such tables as Students, Subjects, Teachers, Classes, etc.
Tables in relational databases can contain links to other tables. The links form relations between the tables as entities in the real world do. That’s why this type of database is called Relational Database.
Are RDBMS and Database the same things?
Many people often confuse the terms Database and RDBMS and are far more likely to use the first one than the latter. In fact, these are two very different things.
A database is a logical unit where your data is stored. Relational Database Management Systems, in contrast, a product that allows you to host your databases, and access and manage them. It defines the internal services, algorithms, and rules of how the database objects are implemented and controlled.
In other words, a database holds and controls data while RDBMS holds and controls the databases.
How many databases can an RDBMS control?
MySQL, PostgreSQL, Oracle
In some Relational Database Management Systems like MySQL and PostgreSQL, you can create as many databases per server instance as you like unless you reach the physical limitations like the memory, storage size of the server, the maximum number of data files, etc.
MS SQL Server
Thus, MS SQL Server does not allow you to have more than 32,767 databases per RDBMS instance. Though you can hardly exhaust this limit, if you do, it is not a problem as SQL Server allows you to detach a database, transfer it to another server and attach it there.
SQLite
As was mentioned before, SQLite is a library rather than a database server, so the limit is related to the maximum number of attached databases per connection. It is 10 by default but can be extended to 125.
How did RDBMS appear?
While each RDBMS is owned by its own company or community, all of them owe their existence to Mr. Edgar Frank Codd, who introduced the relational model in the June of 1972 in his article “A Relational Model of Data Large Shared Data Banks”.
Conclusion
- RDBMS stands for Relational Database Management System
- It is a system providing decent means to host, manage, and access relational databases
- There are multiple Relational DBMSs. Some popular examples are Oracle, Microsoft SQL Server, MySQL, PostgreSQL, and SQLite.
- Most management systems are usually installed as Server Software hosting multiple databases of the same type. The embedded DBMS are exceptional as they are represented only by a library you can use to access a database file via special programming API.
- The history starts from a paper about the relational database model released by Edgar Codd in June of 1980.
- They make data updates slower and require additional space on disk, though. However, it is another story
We use things and rarely think about why they are what they are, don’t we?
The two of the most popular RDBMS 😎 in the world – MySQL and PostgreSQL have quite a story behind them.
PostgreSQL was created by Michael Stonebraker, a computer science professor 👨🏫 who previously worked on the Ingres database project. The new database engine was supposed to solve the contemporary problems of relational database systems by adding support for multiple data types. It was a revolutionary thing breeding from the Ingres project. As it was a post-Ingres deal, it was called Postgres in 1986. Later, when it began to support SQL, it was renamed to PostgreSQL.
MySQL, in turn, has quite a sentimental reason to be called like that. One of the co-founders, Michael “Monty” Widenius gave it the name MySQL which was a combination of his daughter’s name ‘My’ and ‘SQL’. Nowadays this name is in second place after Oracle in the list of the most popular RDBMS❕
Pretty amazing stories aren’t they? 😉
Stay inspired!
Hahaha, check this out homes, we got ourselves a blog post that’s actually useful for beginners, muy bueno! But let me ask you this, since you’re so good at explaining things: what about database normalization? Can you give us a rundown on that too, or is that too advanced for your taste? Come on, don’t leave us hanging here, manito!
Your article helped me a lot, is there any more related content? Thanks!