The first error i see is "WHERE CODE==$CODE" should be "WHERE CODE = $CODE". Your queries could be written a bit more ... professionally: 
$dbh->do(
   'UPDATE INV SET SALESMAN = ? WHERE CODE = ?',
   undef, $SALESMAN, $CODE,
);

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And be sure that you connect with RaiseError set to true while you are at it: 
my $dbh = DBI->connect(
   $data_source, $username, $pass,
   {RaiseError => 1},
);

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UPDATE:
Now i see the real culript: 

my $updy="Y";
$dbh->do("UPDATE INV SET SOLD=$updy  ... ");

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You need to quote that first! 
$dbh->do("UPDATE INV SET SOLD='$updy'  ... ");

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or just use placeholders instead and let DBI do the quoting: 
$dbh->do("UPDATE INV SET SOLD = ? WHERE CODE = ?", undef,$updy,$CODE);

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jeffa

L-LL-L--L-LL-L--L-LL-L--
-R--R-RR-R--R-RR-R--R-RR
B--B--B--B--B--B--B--B--
H---H---H---H---H---H---
(the triplet paradiddle with high-hat)

In reply to Re: Perl Beginners problem with DBI by jeffa
in thread Perl Beginners problem with DBI by Anonymous Monk

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