History of SQL | Evolution of Structured Query Language

Introduction

To fully understand the power and relevance of SQL today, it's important to know where it came from. The history of SQL is deeply rooted in the development of relational database technology, which revolutionized how data is stored, managed, and accessed.



Origins of SQL

The origins of SQL date back to the early 1970s, when IBM researchers Edgar F. Codd, Donald D. Chamberlin, and Raymond F. Boyce were working on ways to manage large volumes of data efficiently. Codd introduced the concept of the relational database model in a groundbreaking 1970 paper titled “A Relational Model of Data for Large Shared Data Banks.”

This model proposed organizing data into tables (relations), a concept that formed the foundation of what would later become SQL.



Development of SEQUEL (1970s)

In the mid-1970s, IBM developed a language called SEQUEL (Structured English Query Language) to implement Codd’s ideas. SEQUEL was designed to be a simple, English-like interface for querying and managing relational data.

However, due to trademark issues, the name SEQUEL was eventually changed to SQL (Structured Query Language). Despite the name change, the pronunciation “sequel” is still commonly used today.



SQL and IBM System R

SQL was first implemented as part of IBM’s System R project, which was the first working prototype of a relational database management system (RDBMS). This project proved that SQL could be used in a real-world environment and demonstrated its potential for commercial use.



Standardization of SQL

As SQL grew in popularity, there was a need for a standardized version of the language that could work across different systems. Here are the key milestones in SQL standardization:

  • 1986 – SQL was adopted as a standard by ANSI (American National Standards Institute).
  • 1987 – It was also recognized as a standard by ISO (International Organization for Standardization).
  • Subsequent versions have been released over the years, including:
    • SQL-89
    • SQL-92
    • SQL:1999 (introduced features like object-relational extensions and recursive queries)
    • SQL:2003 (added XML-related features)
    • SQL:2008
    • SQL:2011
    • SQL:2016
    • SQL:2019 (each adding enhancements for performance, analytics, and interoperability)


Rise of Commercial SQL Databases

Following IBM’s pioneering work, other companies began developing their own relational database systems using SQL. Some of the most notable SQL-based databases that emerged include:

  • Oracle Database (1979)
  • IBM DB2
  • Microsoft SQL Server
  • PostgreSQL
  • MySQL (open-source, released in 1995)

These systems popularized SQL across industries and made it the dominant language for data management in the enterprise world.



SQL in the Modern Era

Today, SQL is used across virtually every industry and platform. It remains the standard language for querying relational databases, and its influence extends into big data, cloud computing, and data analytics platforms such as:

  • Amazon RDS and Redshift
  • Google BigQuery
  • Microsoft Azure SQL
  • Snowflake
  • Apache Hive (SQL-like queries on Hadoop)


Conclusion

The history of SQL reflects the evolution of data management from academic theory to a globally adopted standard. From IBM’s System R to modern cloud databases, SQL has proven to be a robust, scalable, and indispensable tool in the world of data. Understanding its history helps us appreciate why SQL continues to be one of the most in-demand technical skills today.