Chapter 3

The Components of SQL

In This Chapter

arrow Creating databases

arrow Manipulating data

arrow Protecting databases

SQL is a special-purpose language designed for the creation and maintenance of data in relational databases. Although the vendors of relational database management systems have their own SQL implementations, an ISO/IEC standard (revised in 2011) defines and controls what SQL is. All implementations differ from the standard to varying degrees. Close adherence to the standard is the key to running a database (and its associated applications) on more than one platform.

Although SQL isn’t a general-purpose programming language, it contains some impressive tools. Three languages within the language offer everything you need to create, modify, maintain, and provide security for a relational database:

check.png The Data Definition Language (DDL): The part of SQL that you use to create (completely define) a database, modify its structure, and destroy it when you no longer need it.

check.png The Data Manipulation ...

Get SQL For Dummies, 8th Edition now with O’Reilly online learning.

O’Reilly members experience live online training, plus books, videos, and digital content from 200+ publishers.