Mysql large database problem

i have come across an interesting problem when..i have to maintain an enormous size of mysql database(actually the number of rows are supposed to be very big)...now the objective is to insert hundreds of new data once to the mysql database ...also it has to be checked that those data are already not there in database...for example

mysql database contains numbers like (2d, 4f,3f5 ,5h2, j5,4l4,2i4,42,44,d4.....and so on....)

and i have to insert one array (34,2d,fdf3,dd,434,f4)...Here "2d" element is already in above database so it must be neglect during insertion....How can i do this in best way without too much over stretching server resource...are their any php function which can do this directly

thank in advance