SQL Introduction

free php tutorials, php classes, php utilities, free tools What is SQL?
  • Structured Query Language
  • Communicate with databases
  • Used to created and edit databases.
  • Also used to create queries, forms, and reports
What Can SQL do in a database?
  • Can execute queries against a database
  • Can retrieve data
  • Can insert records
  • Can update records
  • Can delete records
  • Can create new databases
  • Can create new tables
  • Can create stored procedures
  • Can create views
  • Can set permissions on tables, procedures, and views

 

Using SQL in Your Web Site

There are many different versions of SQL available for usage.

  • Oracle
  • MySQL
  • SQLite
  • DB2
  • MS SQL
  • PostgreSQL

The popular ones are Oracle and MySQL with MySQL quickly gaining ground. I'll be showing you MySQL. The syntax between SQL domains varies little and with google skills you can adjust this knowledge for SQLite, which I've never used.

What is Database?

A database is a collection of information that is organized so that it can easily be accessed, managed, and updated. In one view, databases can be classified according to types of content: bibliographic, full-text, numeric, and images.
A database management system is a suite of software applications that together make it possible for people or businesses to store, modify, and extract information from a database. A database contains multiple tables.

A Table is an object. Data is stored in Tables Each table has a unique name Columns have various attributes, such as column name and data type Rows contain records or data for the columns

  • Database tables are made of different columns (fields) corresponding to the attributes of the object described by the table.
  • The record is a complete set of information presented within a RDBMS. Records are composed of different fields (columns) in a table and each record is represented with a separate row in this table.
RDBMS

A relational database management system (RDBMS) is a database management system (DBMS) that is based on the relational model as introduced by E. F. Codd. Most popular commercial and open source databases currently in use are based on the relational model.

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