php - Determine if a user came is an organic or direct visit? -

is possible determine whether user has come website via organic search or direct , possible store in our database?

we have form on our website want find out if user came direct or via organic search , pass in form store 'organic' or 'direct' in our database each enquiry.

e.g if user abc came via direct , filled in form stored in database name = abc, referral = direct, enquiry = test.

if user xyz came via organic , filled in form stored in database name = xyz, referral = organic, enquiry = test.

you try request browsers "referrer" parameter. however, method extremely unreliable , unavailable. best option have section (maybe make required) user selects come from.

the reason if found site on google @ work, went home , manually typed in url? count direct visit though search engine. that's why forms typically have dropdown selection.

you grab both referrer choice , use reporting.

update: since mentioned tracking ppc campaign, have few methods can use better track source.

the first method create landing page ad click on to. basically, page identical form on website, instead standalone page or subdomain. page have duplicate form have referral value hard coded in. have unique page/site each campaign source (yoursite/google.aspx, yoursite.com/yahoo.aspx, etc.)

a second method use single form take in submission, in campaign assign querystring variable represent campaign (yourpage.aspx?r=google, yourpage.aspx?r=yahoo, etc.) once user loads page, grab querystring variable , save in session or in cookie. way if browse site , go form, still have referrer.

as always, these methods don't work if click site ad , manually type in @ home. isn't super common happen occasionally.