convert btween types

hi!

i am trying to update a field through bi

the field is like ckmmat_display-pvprs_1,

and the bi field is like bdcdata-fval.

when i am trying to pass the value 4.3 to char field i get only 4.

what is the type that i have to use in order to later on update the bi(bdcdata-fval) with this field.

thanks