A Poll/Rating system in PHP and MySQL

Before you start this lesson, please read the following lessons for your reference:

• Using phpMyAdmin Create Database
• Insert Form Data into Database
• Retrieve data from Database

This lesson will show you how to create a simple poll/rating system in PHP and MySQL. The could be used for any number of items you want to rate without changing a bit.

You may use it to do opinion poll, rate your software,images, news, music,anything.

Here is the example:

This tutorial includes 3 sections:

1. Create database : how to save polling/rating results in MySQL
2. Dealing poll/rate Form: how to saving polling/rating result to database and how to set cookie to prevent client repeat voting on the same item.
3. Retrieve poll/rate result: retrieve poll/rate result for item and assign corresponding poll/rate icon to it.

Poll database in MySQL

We need a database to save polling/rating result, such as item id (which software is rated), how many times rated and the average rating/polling result.

The following is the SQL query for creating a polling table in MySQL.

CREATE TABLE `polling` (
`itemid` INT NOT NULL ,
`votes` INT NOT NULL ,
`result` DECIMAL( 2, 1 ) NOT NULL ,
PRIMARY KEY ( `itemid` )
) TYPE = MYISAM ;

Using phpMyAdmin Create Database could show you how to use PhpMyAdmin to create above table. Note that for result column, which has type DECIMAL(2,1), you need put 2,1 in "Length/Values*" field, shown in the following image:

Decimal(2,1) means result column has 2 digits in total, one digit after digit point. Since we only want rate our items like: no rating(0),bad(1),fair(2), good(3),very good(4) and excellent(5), the average result will be between 0.0 and 5.0,like 3.2, 4.5, etc. If you want more precise result, you may use more digits in decimal type, for example Decimal(7,4).

In this lesson, we make rating on one item for demo purpose. Before we do the polling/rating, the rated item should exist in database.

You may use PhpMYAdmin input the following record to your polling table:

itemid : 1, votes: 0, result: 0.

In PHHMYAdmin panel, click on Insert tab and input data like the following image: