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What is SQL?

• SQL stands for Structured Query Language, full name Structured Query Language.
• SQL allows you to access and manipulate databases, including data insertion, querying, updating, and deletion.
• The SQL language uses English keywords, making it easy to read and write.
• SQL is standardized by the International Organization for Standardization (ISO) and the American National Standards Institute (ANSI).
• SQL provides rich functionality for manipulating data, from simple queries to complex database management operations.

What can SQL do?

• SQL executes queries against databases
• SQL can retrieve data from databases
• SQL can insert new records into databases
• SQL can update data in databases
• SQL can delete records from databases
• SQL can create new databases
• SQL can create new tables in databases
• SQL can create stored procedures in databases
• SQL can create views in databases
• SQL can set permissions on tables, stored procedures, and views

SQL is a standard - but...

Although SQL is a computer language standardized by ANSI (American National Standards Institute), there are still many different versions of the SQL language.

However, to be compatible with the ANSI standard, they must support some major commands in a similar way (such as SELECT, UPDATE, DELETE, INSERT, WHERE, etc.).

Note: In addition to the SQL standard, most SQL database programs have their own proprietary extensions!

Using SQL in Your Website

To create a website that displays data from a database, you need:

• RDBMS database program (e.g., MS Access, SQL Server, MySQL)
• Using a server-side scripting language, such as PHP or ASP
• Using SQL to get the data you want
• Using HTML / CSS

RDBMS

RDBMS stands for Relational Database Management System, full name Relational Database Management System.

RDBMS is the foundation of SQL, and likewise the foundation of all modern database systems, such as MS SQL Server, IBM DB2, Oracle, MySQL, and Microsoft Access.

In RDBMS, data is stored in database objects called tables.

A table is a collection of related data items and consists of columns and rows.

History of SQL Development

The following are key milestones in the history of SQL:

1970s: Origins and Early Development

• 1970: Edgar F. Codd published the paper “A Relational Model of Data for Large Shared Data Banks,” introducing the concept of the relational database and laying the theoretical foundation for SQL's development.
• 1973-1974: IBM researchers Donald D. Chamberlin and Raymond F. Boyce developed a language called SEQUEL (Structured English Query Language) based on Codd's theory, to operate and manage IBM's System R relational database.
• 1976: SEQUEL was renamed to SQL (Structured Query Language).

1980s: Standardization and Commercialization

• 1981: IBM introduced the commercial relational database systems SQL/DS (Database System) and DB2 (Database 2).
• 1986: The American National Standards Institute (ANSI) released the first SQL standard ANSI SQL-86 (SQL-87).
• 1987: The International Organization for Standardization (ISO) also adopted ANSI SQL-86 as an international standard.

1990s: Extensions and Improvements

• 1992: The SQL-92 (SQL2) standard was released, significantly expanding SQL language functionality, including support for new data types, nested queries, and joins.
• 1999: The SQL:1999 (SQL3) standard was released, introducing object-relational database (ORDBMS) features, recursive queries, triggers, and user-defined functions.

2000s: Ongoing Evolution and New Features

• 2003: The SQL:2003 standard was released, introducing XML-related features and window functions.
• 2006: The SQL:2006 standard was released, mainly enhancing support for XML.
• 2008: The SQL:2008 standard was released, further improving syntax and performance optimization.

2010s: New Features and Big Data Support

• 2011: The SQL:2011 standard was released, adding support for datetime data types and temporal data.
• 2016: The SQL:2016 standard was released, introducing the JSON data type and related operation functions, adapting to NoSQL databases and big data processing needs.

2020s: Modernization and Standard Updates

• 2023: The latest SQL standard continues to improve, adding support for more modern database needs and features.

Summary: SQL has evolved from a query language based on the relational model into the core language of modern database management, with its standards continually evolving and expanding. Major database management systems (such as MySQL, PostgreSQL, SQLite, SQL Server, Oracle, etc.) build upon the SQL standard, adding their own extensions and optimizations, making SQL a powerful tool for data manipulation and management. The development of SQL not only reflects technological progress but also reflects changes and growth in data management needs.