What is SQL?
SQL stands for Structured Query Language. SQL language is used to create, transform and retrieve information from RDBMS (Relational Database Management Systems). SQL is pronounced SEQUEL. SQL was developed during the early 70’s at IBM.
Most Relational Database Management Systems like MS SQL Server, Microsoft Access, Oracle, MySQL, DB2, Sybase, PostgreSQL and Informix use SQL as a database querying language. Even though SQL is defined by both ISO and ANSI there are many SQL implementation, which do not fully comply with those definitions. Some of these SQL implementations are proprietary. Examples of these SQL dialects are MS SQL Server specific version of the SQL called T-SQL and Oracle version of SQL called PL/SQL.
SQL is a declarative programming language designed for creating and querying relational database management systems. SQL is relatively simple language, but it’s also very powerful.
SQL can insert data into database tables. SQL can modify data in existing database tables. SQL can delete data from SQL database tables. Finally SQL can modify the database structure itself – create/modify/delete tables and other database objects.
SQL uses set of commands to manipulate the data in relational databases. For example SQL INSERT is used to insert data in database tables. SQL SELECT command is used to retrieve data from one or more database tables. SQL UPDATE is used to modify existing database records.