Structured Query Language

What is SQL?

SQL, an abbreviation for Structured Query Language, is a language used to execute a set of instruction directed to a database. When you go to an auto-teller machine, to withdraw money, you need to press certain button, to instruct the machine what to do, when you go to the Internet, you use your keyboard or mouse to navigate or search for your favorite website, you are telling your machine what to do. All this are possible with the help of SQL. It is a universal language that receives instruction from a “front-end” object that will then compile and send the instruction back to a “back-end” object. The front-end object is an application tool, such as VB, C++, and the back-end object, is a database system, that helps to store data. The instruction received from a front-end application, generally perform the following task:

• Select existing data
• Insert new data
• Update existing data
• Delete existing data

SQL is a language governed by the American National Standards Institute (ANSI), a standard committee that consists of database experts from industry and software vendors. Thus, SQL is a universal and open language, meaning that, it is not owned by any industry.

Transact-SQL

DBMS, or database management system, is a software product that holds and store data. A number of famous DBMS worth noting, are, IBM DB2, MySQL, Sybase Adaptive Server, Oracle, Microsoft Access, and Microsoft SQL Server. These various DBMS, would have their own type of SQL version, generally differ in terms of syntax and features, but, they all complied to the American National Standards Institute (ANSI) SQL Standard. In our exercise contained in this book, we will be using Microsoft SQL Server as our DBMS in employing the use of Transact Structured Query Language (T-SQL), Microsoft’s version of SQL.