SQL ( Structured Query Language) is a special-purpose programming language designed for managing data in relational database management s...
SQL ( Structured Query Language) is a special-purpose programming language designed for managing data in relational database management systems (RDBMS).
Originally based upon relational algebra and tuple relational calculus, its scope includes data Insert, query, Update and Delete schema creation and modification, and data access control.
SQL was one of the first commercial languages for Edgar F. Codd's relational model, as described in his influential 1970 paper, "A Relational Model of Data for Large Shared Data Banks". Despite not adhering to the relational model as described by Codd, it became the most widely used database language. Although SQL is often described as, and to a great extent is, a declarative language, it also includes procedural elements. SQL became a standard of the American National Standards Institute (ANSI) in 1986, and of the International Organization for Standards
(ISO) in 1987. Since then, the standard has been enhanced several times
with added features. However, issues of SQL code portability between
major RDBMS products still exist due to lack of full compliance with, or
different interpretations of, the standard. Among the reasons mentioned
are the large size and incomplete specification of the standard, as
well as vendor lock-in.
More into SQL Concepts and Implementation
SQL STATEMENTS and KEYWORDS
- SELECT Statement
- SELECT DISTINCT Statement
- INSERT Statement
- UPDATE Statement
- DELETE Statement
- GROUP BY Statement
- CREATE INDEX Statement
- DROP INDEX, TABLE AND DATABASE
- ALTER TABLE Statement
- AUTO INCREMENT FIELD
- SELECT INTO Statement
- CREATE DATABASE Statement
- CREATE TABLE Statement
- SQL ORDER BY Keyword
- WHERE Clause
- HAVING Clause
SQL OPERATORS
- SQL AND and OR Operators
- FULL JOIN Keyword
- UNION Operator
- LIKE Operator
- IN Operator
- BETWEEN Operator
- SQL Alias
- JOIN
- INNER JOIN
- LEFT JOIN
- RIGHT JOIN
SQL FUNCTIONS
SQL CONSTRAINTS
- SQL PRIMARY KEY Constraint
- SQL FOREIGN KEY Constraint
- SQL CHECK Constraint
- SQL DEFAULT Constraint
- SQL NOT NULL Constraint
- SQL UNIQUE Constraint
- SQL VIEWS
- NULL Values