store the clicks

I am creating an application where there is a registration control and a login control i have created and attached to sql server now i want that when a logged in user click that button the number of clicks should be store in a table which have only two coloum username and clickcounts ,now the point is how will i check that a user is online and the number of clicks will store in clickcounts coloum the clicks should be incremented. Please help me ignitesofthelp@gmail.com Thanks a lot !
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