The Structured Query Language (SQL) is the computer language in which a user or an application communicates with an SQL-capable database system. SQL database systems include PostgreSQL, MySQL, Oracle, and many others in popular use. The language is standardized by the American National Standards Institute (ANSI) and the International Organization for Standardization (ISO), but many database systems provide their own extensions to the standard or do not fully implement the standard. These extensions typically extend SQL functionality into an altogether different programming language or markup language. SQL was first developed in the early 1970s for use with System R, a database system created by IBM.

The Structured Query Language SQL is the computer language in which a user or an application communicates with an SQL capable database system SQL database systems include PostgreSQL MySQL Oracle and many others in popular use The language is standardized by the American National Standards Institute ANSI and the International Organization...
Like any technology that strives to be interoperable among different implementations SQL has been standardized The first SQL standard was adopted and published by the American National Standards Institute ANSI in 1986 The standard was further ratified by the International Organization for Standardization ISO in 1987 and ISO continues to be the...
SQL Overview The SELECT command in SQL provides a robust means for retrieving data from a database More specifically SELECT returns a result set of zero or more rows from the database and this result set corresponds to the query that was executed The result set is calculated by the query optimizer inside the database system based on the information...
SQL Table Commands Overview As mentioned previously in this series of SQL articles databases are primarily composed of tables The columns and rows” structure of the table allows data to be efficiently inserted manipulated updated and deleted from the database The three most important commands used to work with tables CREATE TABLE...
SQL Keys Overview In SQL keys are used to maintain referential integrity among relations Put simply this means keys allow tables to reference each other and each reference will be correct” every time Referential integrity also prevents records from being dangled” or orphaned” by another record that has been...
SQL Programming Overview Anybody who has done something for a long time has probably wanted to change how things work at some point or another A worker at a mill might have found a more efficient way of cutting logs or a mathematics teacher might have had a hand in changing a school’ s algebra curriculum SQL lets you change how things work...
SQL Programming Overview In the article SQL Programming we discussed creating the Hello World function in PostgreSQL MySQL and Oracle In this article we take Hello World one step farther and introduce the parts of a function and how to pass parameters to a function This article uses PostgreSQL’ s PL pgSQL...
Procedural languages provide the fundamental method for programming within an SQL database In other articles in this series we have covered the SQL based procedural languages but those are generally not the only procedural languages found in an SQL database Procedural extensions for Perl and Java tend to be the most popular additions but some database...
SQL Data Types Overview In SQL as in many other programming languages every piece of data has a particular type For example 11 is an integer and Wall Street” is a text string The SQL standard defines many data types to accommodate almost any type of data Some cases arise where the SQL standard does not adequately support certain...