php expert -- 2

we need someone expert in php ( oop) we are having an online game based on browser it's about servers " worlds " our database is divided into 2 main structure , meaning we have 1 primary database and second that holds the server when a player signed up for the first time that will be ok , but when he wants to use same data in another server it will show him error that the data is already there , we used to use ajax to apply another function to get pass this issue ( i have old code ) but now we are not using ajax we changed our style to a normal form post so we got stuck now we already have the php function prepared we only need someone knows when to call it ( prepare if statement )