Web Design

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CHAPTER

Adding Information from a Database 13

SQL Syntax

SQL is designed to be fairly easy to learn and use. It is
comprised of a series of command words or phrases, all in
simple English. For example, if you want to add data to a
table, you use the INSERT INTO command.

TABLE

INSERT INTO

INSERT INTO

SQL Language Subsets

SQL is divided into three sublanguages: the Data Definition
Language (DDL), the Data Manipulation Language (DML), and the
Data Control Language (DCL). The DDL is the subset of SQL that
allows you to create, alter, and delete the actual tables themselves.
By far the most commonly used subset of SQL is the DML. These
commands allow you to interact with your data. The DCL is the
subset of SQL that allows you to create and manage user accounts.

DDL

DML DCL

Structured Query Language

Also in the 1970s, a group of developers at IBM developed the Structured
Query Language (SQL). SQL allows developers to write code to execute
commands against a database. It allows developers to work with relational
databases through a powerful language that nonetheless relies on a fairly
clear syntax.

SQLSQL