Introduction

What is SQL?

• SQL stands for Structured Query Language

• SQL lets you access and manipulate databases

• SQL is an ANSI (American National Standards Institute) standard

• SQL(Structured Query Language) is a special-purpose programming language designed for managing data held in a relational database management system (RDBMS), or for stream processing in a relational data stream management system (RDSMS).

Brief Introduction

Abbreviation of structured query language, and pronounced eithersee-kwell or as separate letters. SQL is a standardized query language for requesting information from a database. The original version called SEQUEL (structured English query language) was designed by an IBM research center in 1974 and 1975. SQL was first introduced as a commercial database systemin 1979 by Oracle Corporation.

Historically, SQL has been the favorite query language for database management systems running on minicomputers andmainframes. Increasingly, however, SQL is being supported by PCdatabase systems because it supports distributed databases(databases that are spread out over several computer systems). This enables several users on a local-area network to accessthe same database simultaneously.

Although there are different dialects of SQL, it is nevertheless the closest thing to a standard query language that currently exists. In 1986, ANSI approved a rudimentary version of SQL as the official standard, but most versions of SQL since then have included many extensionsto the ANSI standard. In 1991, ANSI updated the standard. The new standard is known as SAG SQL.

What Can SQL do?

• SQL can execute queries against a database

• SQL can retrieve data from a database

• SQL can insert records in a database

• SQL can update records in a database

• SQL can delete records from a database

• SQL can create new databases

• SQL can create new tables in a database

• SQL can create stored procedures in a database

• SQL can create views in a database

• SQL can set permissions on tables, procedures, and views