What Is SQL?

This section provides a quick introduction of SQL (Structured Query Language), a comptuer language that allows users to interact with RDBMS to define create data structure and manage data instances.

What Is SQL? SQL (Structured Query Language) is a comptuer language that allows users to interact with Relational Database Management Systems (RDBMS) to define data type and structure, and to insert, update or delete data instances.

Usually, an RDBMS system will offer a user interface (UI) to allow you to issue SQL statements to directly operate on the RDBMS system:

User <--> UI <--SQL--> RDBMS <--> Data storage

A typical RDBMS system does also offer Application Programming Interface (API) to allow application programs to use SQL statements to interact with the RDBMS system:

User <--> Application <--SQL--> RDBMS <--> Data storage

SQL is a non-precedural language. Each SQL statement is an individual execution unit, independent of other statements. There is no conditional statements, jumping statements or looping statements to group multiple statements together into a complext execution unit. There is no way to define a procedure of statements, and no procedure call statements.

Last update: 2015.

Table of Contents

 About This Book

Introduction of SQL

What Is SQL?

 SQL History and Revisions

 SQL and Database Terminologies

 MySQL Introduction and Installation

 Introduction of MySQL Programs

 Perl Programs and MySQL Servers

 PHP Programs and MySQL Servers

 Java Programs and MySQL Servers

 Datatypes and Data Literals

 Operations and Expressions

 Character Strings and Bit Strings

 Commonly Used Functions

 Table Column Types for Different Types of Values

 Using DDL to Create Tables and Indexes

 Using DML to Insert, Update and Delete Records

 Using SELECT to Query Database

 Transaction Management and Isolation Levels

 Locks Used in MySQL

 Defining and Calling Stored Procedures

 Variables, Loops and Cursors Used in Stored Procedures

 Outdated Tutorials

 References

 PDF Printing Version