Who is the inventor of the relational database model and SQL?

Dr. Edgar F. Codd invented the relational database model in 1970 at IBM. Donald D. Chamberlin and Raymond F. Boyce subsequently created the SEQUEL (Structured English QUEry Language) query language at IBM's San Jose Research Laboratory, which evolved into SQL.

Why was the name changed from SEQUEL to SQL?

The language was originally named SEQUEL. However, the acronym was a registered trademark of the Hawker Siddeley aircraft company in the UK, so IBM shortened the name to SQL (Structured Query Language).

What is the most widely supported ANSI SQL standard version?

SQL-92 (Entry Level) remains the universal baseline supported by virtually every relational database engine worldwide, including standard join syntax, aggregate functions, and subqueries.

History & Evolution of SQL: From Edgar Codd to Modern SQL:2023

To truly master database engineering and excel in university computer science exams, understanding how SQL emerged from academic theory into the undisputed standard of world computing is indispensable. In this chapter, we trace the historical timeline of SQL, examine Dr. Edgar F. Codd's foundational relational model, look at IBM's prototype System R, and break down the major ANSI/ISO standardization milestones from SQL-86 to modern SQL:2023.

The Birth of Relational Theory: Dr. Edgar F. Codd (1970)

Before 1970, computerized data storage relied entirely on hierarchical and network database models (such as IBM's IMS and CODASYL). These legacy systems forced programmers to manually navigate physical memory pointers and disk addresses. If a database schema changed, every single application program had to be completely rewritten.

In June 1970, an Oxford-educated mathematician and IBM researcher named Dr. Edgar F. (Ted) Codd published a groundbreaking paper titled:

"A Relational Model of Data for Large Shared Data Banks" — Communications of the ACM (June 1970).

Dr. Codd proposed separating physical data storage from logical queries using mathematical relational calculus and first-order predicate logic. Data would be viewed logically as tables (relations) of rows (tuples) and columns (attributes), completely hiding disk tracks and memory pointers from application developers.

IBM System R and the Invention of SEQUEL (1974–1979)

Following Codd's publication, researchers at IBM's San Jose Research Laboratory launched a research prototype called System R to prove that a relational database could achieve production-grade performance. Two key IBM engineers, Donald D. Chamberlin and Raymond F. Boyce, designed a query language named SEQUEL (Structured English QUEry Language).

SEQUEL was intentionally modeled after fluent English sentence structure (SELECT ... FROM ... WHERE ...) so that business accountants and researchers could query data without writing low-level procedural assembly or COBOL code. Due to a trademark dispute with the Hawker Siddeley aircraft corporation, SEQUEL was renamed SQL (Structured Query Language).

BCA / CS University Exam Tip: When asked in a viva exam whether SQL stands for "Structured Query Language", note that while commonly accepted, the official ANSI standards committee officially defines SQL as an independent proper name, not an acronym!

Milestone Timeline of SQL Standardization

Year & Standard	Official Name	Key Features Introduced
1979	Oracle V2	Larry Ellison's Relational Software (later Oracle Corporation) releases the first commercial SQL RDBMS ahead of IBM.
1986 / 1987	SQL-86 (SQL1)	Adopted by ANSI and ISO as the first official international database query language standard.
1989	SQL-89	Minor revision adding formal integrity constraints (`PRIMARY KEY`, `FOREIGN KEY`, `UNIQUE`, `CHECK`).
1992	SQL-92 (SQL2)	Major watershed release! Introduced explicit relational joins (`INNER JOIN`, `LEFT JOIN`, `RIGHT JOIN`, `FULL JOIN`), `CASE` expressions, dynamic SQL, and subqueries.
1999	SQL:1999 (SQL3)	Added regular expressions, recursive Common Table Expressions (`WITH RECURSIVE`), triggers, and Object-Relational features.
2003	SQL:2003	Introduced native XML features, sequences, and revolutionary Window Functions (`OVER()`, `ROW_NUMBER()`, `RANK()`).
2008 / 2011	SQL:2008 & SQL:2011	Added temporal tables (system-versioned data), `TRUNCATE TABLE` standard, and `FETCH FIRST` pagination.
2016 / 2019	SQL:2016 & SQL:2019	Added native JSON support (`JSON_OBJECT`, `JSON_ARRAY`, `JSON_VALUE`), polymorphic table functions, and multidimensional arrays.
2023	SQL:2023	The latest ISO standard! Adds Property Graph Queries (SQL/PGQ), enhanced JSON data types, and byte-string operations.

Why SQL Remains Unchallenged After 50+ Years

Despite the rise of NoSQL (MongoDB), Key-Value caches (Redis), and Graph databases (Neo4j) in the 2010s, SQL has proven its unassailable longevity. Modern high-performance distributed engines like Google Spanner, CockroachDB, and Snowflake chose SQL as their primary query interface because relational algebra provides mathematically proven data correctness and query composability.

In our next class, we explore the core RDBMS Concepts & Architecture, where we break down relational tables, keys, and the legendary ACID model!