retreive primary key of inserted record

djwinder

Hi everyone

this is no doubt really simple but here goes:

I have a table of announcements, sometimes but not always people will post a file with the announcement which will go into the documents table. On the occasions when someone does upload a document I would like to retreive the primary key (which is auto incrementing) from the announcements table when the insert had taken place and store it in the documents table with the information on the associated document. This way should someone delete the annoucement i can identify the associated document record and delete that also.

can anyone tell me if there is a way of getting the primary key of a record as you are inserting that record?

Hope that is clear, thanks in advance.

laserlight

can anyone tell me if there is a way of getting the primary key of a record as you are inserting that record?

Probably, but it depends on what database API you are using. For example, you might use PDO->lastInsertId() with the PDO extension.

djwinder

ah ok, kind of lost me there. PDO looks new to me. I just installed the standard PHP5, MySQL and phpmyadmin and have been trying to develop with that since. Does that shed any more light on it?

laserlight

That sounds like you are using the MySQL extension, upon which the correct function is [man]mysql_insert_id/man. That said, I suggest using either the MySQLi extension or PDO extension instead. They both provide an object based interface with support for prepared statements. The PDO extension provides a lightweight database interface that can be used with several database management systems (but it is not a database abstraction layer), but the MySQLi extension may be a little faster.

djwinder

thank you very much for your help with this, if i activate MySQLi will the funcation still work or will it require me to use something else such as mysqli_insert_id at a guess?

laserlight

thank you very much for your help with this, if i activate MySQLi will the funcation still work or will it require me to use something else such as mysqli_insert_id at a guess?

Different programming interface, different functions, of course. Read the PHP manual on mysqli->insert_id. You have the choice of either taking advantage of the object based version (like PDO), or of the procedural version (like the MySQL API).