adding to a database

[martinb7]

Is there any way of making a database column (e.g id) + 1 if someone clicks jim.php for example?

<a href=&quot;jim.php&quot;[/blue]>jim</a>

Is there any way of embedding it to the link or in jim.php?

 

[sleipnir214]

If jim.php is a PHP script which updates that column, sure. Want the best answers? Ask the best questions:

http://www.tuxedo.org/~esr/faqs/smart-questions.html

TANSTAAFL!

 

[KempCGDR]

In Jim.php:
Read value from database
Add one
Write it back

 

[sleipnir214]

KempCGDR:

Your solution is not concurrency-safe. The increment of a value in a database should be performed as an atomic operation.

Suppose the value to be incremented is X. By reading, incrementing and writing as separate operations, the following is very possible:[ol][li]One user reads the value, and gets X.[/li][li]A second user reads the value and gets X.[/li][li]The first user increments the value to X + 1 then writes the new value to the database.[/li][li]The second user then increments the value to X + 1 and does the name.[/li][/ol]
Now the value in the database is X + 1, when it should be X + 2.

Most SQL-based database servers will allow an increment to be performed as such:

UPDATE tablename SET columnname = columnname + 1 WHERE anothercolumn = somecondition. Want the best answers? Ask the best questions:

http://www.tuxedo.org/~esr/faqs/smart-questions.html

TANSTAAFL!