Introduction to SQL

What is SQL?

    SQL stands for Structured Query Language
    SQL lets you access and manipulate databases
    SQL is an ANSI (American National Standards Institute) standard

What Can SQL do?

    SQL can execute queries against a database
    SQL can retrieve data from a database
    SQL can insert records in a database
    SQL can update records in a database
    SQL can delete records from a database
    SQL can create new databases
    SQL can create new tables in a database
    SQL can create stored procedures in a database
    SQL can create views in a database
    SQL can set permissions on tables, procedures, and views

SQL is a Standard – BUT….

Although SQL is an ANSI (American National Standards Institute) standard, there are many different versions of the SQL language.

However, to be compliant with the ANSI standard, they all support at least the major commands (such as SELECT, UPDATE, DELETE, INSERT, WHERE) in a similar manner.

Note: Most of the SQL database programs also have their own proprietary extensions in addition to the SQL standard!
Using SQL in Your Web Site

To build a web site that shows some data from a database, you will need the following:

    An RDBMS database program (i.e. MS Access, SQL Server, MySQL)
    A server-side scripting language, like PHP or ASP
    SQL
    HTML / CSS

RDBMS

RDBMS stands for Relational Database Management System.

RDBMS is the basis for SQL, and for all modern database systems such as MS SQL Server, IBM DB2, Oracle, MySQL, and Microsoft Access.

The data in RDBMS is stored in database objects called tables.

A table is a collection of related data entries and it consists of columns and rows.