Question

I have a requirement to gather a form input and store it into the database. That is pretty easy. The difficult part is that I can not make a unique key on a long text field.

In this kind of a situation, what is usually done to help prevent duplicate entries from being entered by users?

Thanks,
Alex

Answer 1

UPDATED

Direct Question:

You should create an additional field as in this eaxmple

myId int(11) NOT NULL AUTO_INCREMENT,
myText TEXT,
myUnique VARCHAR(255) NOT NULL DEFAULT '0',
UNIQUE KEY myUnique (myUnique)

<form>
<textarea name="myText" ></textarea>
<input type="hidden" value="UNIQUE-ID" name="myUnique" />
</form>

NOTE:

• a UNIQUE-ID can be generated in php in many ways something built-in function are MD5 – SHA1 – RAND – UNIQUEID – TIME – CRC32

EXAMPLE:

$myUnique = crc32("The quick brown fox jumped over the lazy dog.");

Further SO Readings:

• Unique text field in MySQL and php
• What is the best way to check for duplicate TEXT fields in MYSQL/PHP?