conditional search

hello i need this function: a user is asked to input a number (or a code) and this cose is checked so that if it is found in the site database the user go on in another page

I coul ddo with conditionl with some form builder, but the problem is that these code to be searched will be hundred. Si i want to have the possiiblity to insert them all in a table(or whatever) and then the form will check inside the table.

because i have a form builder where i have to insert the condition for each value..if 0= then..if =1 then..And this is very long

IF the check would be in a table that is already populated would be easier for me

Thanks for help