In computer science, there are numerous programming languages, but there is a specific type of language for obtaining data stored in databases based on the relational model. In the year 1970, Edgar Frank Codd created the relational data model by creating a “sub-language” to manage access to data.
The spread of dynamic web pages through the Internet today is mainly due to the possibility that their content is handled through databases. Database management is a complicated process, which has been considerably streamlined by the SQL language. As its full name (Structured Query Language) implies, the SQL language is responsible for making queries and editing the information stored in a certain database management system.
The origins of SQL take us to the 1970s when in the IBM laboratories, the new System R database software was created. In the beginning, it was called SEQUEL, a name that is still used as an alternative pronunciation for SQL but was later renamed to SQL only.
In 1979, a company called Relational Software, which later became Oracle, saw the commercial potential of the SQL language and launched its own modified version, called Oracle V2.
The SQL language offers great flexibility to the users supporting distributed databases, that is, databases that can be executed in several computer networks at the same time. Certified by ANSI and ISO, the SQL language has become a standard of database query language is the basis of a wide variety of well-established database applications on the Internet today.
It serves both for business purposes and for academic needs and works in both individual teams and company servers. With the advancement in database technology of SQL-based applications has become increasingly affordable for the normal user. This is due to the introduction of various open source SQL database solutions such as MySQL.
The SQL language quickly became popular and was included in the most popular database managers such as Microsoft SQL Server, Oracle, Sybase, MySQL, Firebird, Informix, PostgreSQL, DB2, and so on. And in addition to database managers, many programming languages base their data access engines on the use of SQL commands to execute the data movements of applications developed in their environment.
The SQL world is surrounded by many concepts such as insertion, update, query, subquery, trigger or trigger, procedure, and so on. Also, the commands used in SQL to execute the different actions can be very simple to obtain very general data, even very complex to obtain fewer general data using, for example, subqueries that can be very complex.
Over the years, the SQL standard has been updated to adapt to new technologies; for example, in 2005 the SQL standard was adapted to define how to import and export XML files that began to be elements of global use in computing.
However, although there is a standard defined by ANSI, there are particularities among the different database managers in SQL management. For example, The Oracle SQL language is not the same as the Microsoft SQL Server; Normally the differences are minimal, but they exist. Also, parallel to the SQL, the different database managers created different adaptations to develop small programs directly in the database manager -without resorting to an external programming language- that they use, mainly, SQL. For example, in SQL Server there are stored procedures, and in Oracle, there is PL / SQL, which is an embedded programming language.
Although the idea of the stored procedure starts from extending an SQL language destined to the execution of single commands to create programs, those programs embedded in the database managers incorporate notable differences when comparing those of one database manager with another.
Currently the SQL standard, whatever its environment of execution, it is essential for any developer of computer applications to focus on the speciality of management computing. Mastering the SQL language is very important for the performance of the work of a programmer.