perl: executing stored procedure which uses select - oracle

Question

I am running into some errors when trying to run a stored procedure through Perl.
The following statements work fine in sqlDeveloper and return expected results
EXEC alpha.beta.do_something()
This does not generate any output, as expected
Select alpha.beta.get_something(alpha.STRING_ARRAY('xyz')) from tableName
This generates output which is given to us from the DBA guys. It has this format in DB terms: Output Type:Ref Cursor. The cursor has two columns, a and b
When running through Perl, I get errors when running the second statement.
This is the Perl code that I am using:
sub execute_procedure {
my $dbh = shift;
my $procedure = shift;
my $statement = "BEGIN $procedure; END;"
my $sth;
eval {$sth = $dbh->prepare($statement);};
eval {$sth->execute();};
if ($#) {
print "failed";
} else {
print "passed";
}
}
# Call 1
execute_procedure($dbh, "alpha.beta.do_something()")
# Call 2
execute_procedure($dbh, "Select alpha.beta.get_something(alpha.STRING_ARRAY('xyz')) from tableName")
Call 1 works as expected, does not generate any errors
Call 2 results in this error
"Select alpha.beta.get_something(alpha.STRING_ARRAY('xyz')) from
tableName" results in :PLS-00428: an INTO clause is expected in this
SELECT statement (DBD ERROR: error possibly near <> indicator at char
6 in 'BEGIN <>Select alpha.beta.get_result(alpha.STRING_ARRAY('xyz'))
from tableName; END;')
if I remove BEGIN and END from the statement in the execute_procedure function like this:
# my $statement = "BEGIN $procedure; END;";
my $statement = "$procedure";
then it does not generate any error, but it returns a result which I don't know how to parse
my $result = $sth->fetchrow_hashref;
print Dumper($result)
results in:
$VAR1 = {
'alpha.beta.get_result(alpha.STRING_ARRAY(\'xyz\'))' => bless( {}, 'DBI::st' )
};
so, my questions are
What is the right way to execute a stored procedure which uses the SELECT statement? Should it be called with BEGIN $procedure; END; or without the BEGIN/END?
How can I get the actual data from bless( {}, 'DBI::st' )? I have tried to use different fetch options: fetchrow, fetchrow_hashref etc. but I am not able to get the actual data from the object

Answer 1

$VAR1 = { 'alpha.beta.get_result(alpha.STRING_ARRAY(\'xyz\'))' => bless( {}, 'DBI::st' ) };
The value here is a DBI statement handle. It's the same thing you get when you do my $sth = $dbh->prepare(...). It's probably been executed already, so you can just call any of the fetch methods on it.
my $result = $sth->fetchrow_hashref;
while (
my $res = $result->{'alpha.beta.get_result(alpha.STRING_ARRAY(\'xyz\'))'}
->fetchrow_hashref
) {
# ...
}
But that looks horrible, and you might not know what the keys are. So you might want to just iterate over all of them.
my $result = $sth->fetchrow_hashref;
foreach my $key ( keys %${ $result } ) {
print "Processing results of $key\n";
while ( my $res = $result->{$key}->fetchrow_hashref ) {
# do things with the $res
}
}
You just need to figure out a good way to deal with the results. The above loop also works if there is just one key in the hash ref, so you could just use it anyway and hope that there is always just one.