SQL has a long history in the development of relational database systems. It was created to provide a practical way to work with data stored in relational databases.
The history of SQL is closely connected with the development of the relational database model.
In 1970, computer scientist Edgar F. Codd published a landmark paper describing the relational model for databases.
The relational model introduced the idea of organizing data into tables and using relationships between data items.
Edgar F. Codd worked at IBM Research and proposed the relational model as a new approach to organizing database information.
Instead of organizing information only through complex navigational structures, the relational model represented information using relations, which are commonly represented as tables.
Student
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ID | Name | Course
1 | Rahul | Python
2 | Priya | SQL
3 | Amit | JavaIBM researchers began developing a relational database system based on the relational model.
At IBM's San Jose Research Laboratory, researchers including Donald D. Chamberlin and Raymond F. Boyce worked on a language for interacting with relational databases.
This work eventually led to SQL.
The language was initially called SEQUEL, which stood for Structured English Query Language.
It was designed to provide a relatively simple way for users to query and manipulate data in relational database systems.
The name was later changed to SQL.
IBM developed System R, an important experimental relational database system.
SEQUEL was used as the query language for System R and helped demonstrate that the relational database model could be implemented in a practical database system.
SQL was designed to make it easier to interact with relational databases.
Users could write declarative statements describing the data they wanted instead of specifying every low-level step required to retrieve that data.
For example:
SELECT name
FROM students;This query describes the data that should be returned.
As relational database systems became more important, SQL became a widely used language for querying and managing relational data.
Different database products implemented SQL with their own extensions, while the core language continued to develop through standardization.
SQL was standardized so that there could be a common language specification across different database systems.
The American National Standards Institute (ANSI) and the International Organization for Standardization (ISO) have been involved in SQL standardization.
This helped establish a common foundation for SQL implementations.
One of the major milestones was the first ANSI SQL standard, published in 1986.
It is commonly referred to as SQL-86.
This standard provided a formal specification for important parts of the SQL language.
The SQL standard was revised in 1989.
This version is commonly called SQL-89 and included additional improvements and integrity-related features.
A major revision was published in 1992 and is commonly known as SQL-92 or SQL2.
It significantly expanded and refined the SQL language and became an important reference point for SQL implementations.
The SQL standard was further revised in 1999.
This version introduced or expanded features such as recursive queries, triggers and procedural extensions within the standard.
It is commonly referred to as SQL:1999.
Another major revision appeared in 2003.
SQL:2003 added and refined several features, including improvements related to XML and other database capabilities.
The SQL standard was updated again in 2008.
The revision continued to improve SQL features and standardize database behavior.
The SQL standard was revised in 2011.
This revision included important standard features related to temporal data and other database capabilities.
SQL:2016 continued the development of the SQL standard.
It included additional capabilities, including features related to JSON and row pattern recognition.
The SQL standard continues to evolve. The SQL:2023 revision added and updated features for modern database requirements.
Different database products may implement different portions of the SQL standard and may also provide their own extensions.
SQL is a language standard, while database systems provide implementations of SQL.
Examples include:
Each system supports SQL but may have its own features and syntax extensions.
SQL remains an important technology for applications that use relational databases.
It is used in areas such as:
1970
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Codd's Relational Model
1970s
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IBM develops SEQUEL
1980s
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SQL becomes widely used
1986
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ANSI SQL Standard
1989
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SQL-89
1992
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SQL-92
1999
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SQL:1999
2003
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SQL:2003
2008
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SQL:2008
2011
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SQL:2011
2016
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SQL:2016
2023
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SQL:2023Modern applications commonly combine SQL with programming languages and frameworks.
Frontend
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Backend
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SQL
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Relational DatabaseFor example, a Python, PHP, Java or C# application can use SQL to retrieve and manage relational data.
Question: Who proposed the relational database model in 1970?