On a webapp I've used trigger to auto populate some tables. Because using triggers isn't commonly allowed to the public web hosts, I'll like to implement the triggers functionality from php code.
Do you have any advice about how can I do that?
Just to make sure I am getting your point, PHP cannot cause your trigger to fire - that is an instruction "hardwired" and internalized within the Mysql engine - that is my understanding anyway.
If your question is "how to you take the instructions in your triggers and have them run another way?" all I can suggest is that you
1 replicate the instructions in SQL statements
2 have PHP run those SQL statements when an event happens, and/or,
3 have cron call upon PHP to run the script against a time schedule