The first version of SQL was developed at IBM by Donald D. Chamberlin and Raymond F. Boyce in the early 1970s. This version, initially called SEQUEL, was designed to manipulate and retrieve data stored in IBM's original relational database product, System R. The SQL language was later formally standardized by the American National Standards Institute in 1986. Subsequent versions of the SQL standard have been released as International Organization for Standardization (ISO) standards... more

The MySQL® database has become the world's most popular open source database because of its consistent fast performance, high reliability and ease of use. It's used in more than 11 million installations ranging from large corporations to specialized embedded applications... more

Structured Query Language (SQL)

Definition: SQL is a powerful yet easy to learn computer language. It provides a standardised toolkit through which database designers, managers, administrators and users can efficiently manage data in Relational Database Management Systems.


Structured Query Language

An SQL 'query' (a command or series of related commands) is passed to the database engine which processes the instructions it contains. Any results are then returned the querier. An SQL query may be as simple as retrieving one record from the database, or as complex as multi-step filtering of data based on multi-level criteria. Efficient use of SQL can help to save bandwidth, time and processor usage in complex situations.

What is it? SQL is, at its heart, a programming language. An SQL 'query' manifests itself as a series of commands or statements; queries can include arithmetic calculations and can use query elements or procedures stored in the system. SQL databases are designed from the start using SQL queries – these designs (or 'schema') can be very complicated, and the proper design of complex examples is a specialist area in itself.

The SQL language is used to ask the database questions about the data stored inside: “what is the value of the element stored in this index?”, or “what is the relationship between these sets of data?”. Manipulative commands, such as “Please insert this data” or “please update this record as follows” are also issued using SQL queries (properly the commands which actually alter the stored data are referred to as the Data Manipulation Language (DML)). A Data Definition Language (DDL) allows SQL queries to create and administer the data structures, the 'tables' of data, that constitute the database. The actual syntax used is a little more strict and regimented than these natural language phrases suggest, but in effect this is the type of communication that will take place between a relational database and the person or device querying it using SQL.

SQL is standardised by ANSI (American National Standards Institute), but many dialects exist and while the principles remain largely the same between different implementations, some of the detail does differ


There are many differing ways in which databases can be created and used, and SQL is just one way of them. Its standardisation, though, as well as the omnipresence it enjoys throughout the computing industry means that it is the natural choice for most users and applications. Popular dialects of SQL are used in, amongst others, Microsoft applications (Microsoft Access), the widely used Oracle database system, and MySQL (a very widely adopted free implementation). For SQL queries to be used on a database, it must be formatted to be compatible, and this must be done from inception. Retrospectively changing a data storage engine to be compatible is simply not practical.

Database servers are commonly used with web applications, large-scale database-driven websites, web applications, large intranets and many other examples of enterprise-level 'distributed computing'. Widespread take-up is assisted and encouraged by the compatibility of many existing programming languages with different SQL implementations.

How Can It Help Businesses?

A properly designed and maintained database is essential for the use or manipulation any non-trivial data collection. Whether the database manifests itself as an alphanumerically ordered filing cabinet, a spreadsheet, or a fully fledged relational SQL database on a dedicated server, the information needs to be ordered in a sensible manner.

Depending on the implementation used, SQL offers excellent protection to data. Integrity of data can be maintained, duplicates easily identified and removed, and simultaneous access and updates to the same record can be safely administered and recovered from, where necessary. The speed at which the implementation will run depends on the way in which the SQL database is set up from the outset and upon the efficiency of the SQL statements used, but in all cases it is likely to improve upon manual and custom-made solutions such as spreadsheets (and the filing cabinets discussed earlier).

SQL is so frequently used in the industry that it represents a natural choice for many organisations: it may be possible to integrate much of an company's existing software applications with an SQL implementation, and clearly this is of great financial benefit. Coupling this with the large number of freely available resources and help materials, tools, and the shallow learning curve required in the initial learning steps, means that SQL often represents and natural choice.