looking for a quick and light storage solution for php - simpleXML?

i want to use simplexml & a webform to capture some simple information but i'm worried that if someone submits the form at precisely the same moment i might lose some data.

how can i ensure this doesn't happ开发者_运维技巧en?

If you don't mind those users waiting for eachother you could implement a simple lock using flock. Anything more complex will require a database of some sorts to ensure atomicity.