my $col_name = 'P_DLRUOM';
my $entered_value = 'p_dlruom';

sub check_colname {
    if ($col_name eq $entered_value) {
        return 'equal';
    };
    return 'not equal';
};

##</code><code>##


sub validate_fields {
    my ($colvalue,$colname) = @_;

    if ($colname eq 'P_DLRUOM') {
        warn "Checking '$colvalue' for validity in 'P_DLRUOM':";
        return validate_p_dlruom( $updateval );
    } elsif ($colname eq 'FOO') {
        warn "Checking '$colvalue' for validity in 'FOO':";
        return validate_foo( $updateval );
    } else {
        warn "Unknown column name '$colname' passed.";
        return;
    };
};

##</code><code>##

# Map the column name to the validator code:
my %validator = (
    P_12MONTHDEMANDQTY => \&validate_number,
    ...
    P_DLRUOM => \&validate_p_dlruom,
    ...
);

sub validate_fields
{
    my ($updateval, $colname) = @_;
    if (! exists $validator{ $colname }) {
        warn "'$colname' is not a valid column name.";
    };
    my $code = $validator{ $colname };
    if (! $code->($updateval, $colname)) {
        warn "'$updateval' is not a valid value for '$colname'.";
    } else {
        warn "'$updateval' is a valid value for '$colname'.";
        return 1
    };
}