in reply to DBI and arrays

From the fine docs:
$ary_ref = $dbh->selectall_arrayref($statement, \%attr, @bind_values);

So selectall_arrayref expects a hash reference as second argument, which you didn't pass. If you don't want to pass any %attr's, just pass undef (or if that doesn't work, a reference to an empty hash, {}) as second argument.

Perl 6 - second systems done right

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Re^2: DBI and arrays
by Anonymous Monk on Jan 17, 2012 at 11:59 UTC
    Using Data::Dumper I print @SQLvars like so, before executing the query 
    warn Dumper \@SQLvars;

    [download]
    I see the array printed, with 4 items in each row of the array, like this 
    $VAR1 = [
          {
            'COLX' => 'TESTA1',
            'COLY' => 'TESTA2',
            'COLZ' => 'TESTA3'
          },
          {
            'COLX' => 'TESTB1',
            'COLY' => 'TESTB2',
            'COLZ' => 'TESTB4'
          },

    [download]
    I then execute the query 
    my $sth = $dbh->prepare($SQLQueryString);
my $array_ref = $dbh->selectall_arrayref( $SQLQueryString, { Slice => 
+{} }, @SQLvars );

    [download]
    Which returns this error 
    DBD::Oracle::db selectall_arrayref failed: called with 9 bind variable
+s when 3 are needed

    [download]
    For the life of me I can't work out why it thinks there should be 9. If you or anyone else can advise that'd we great.
[reply]
[d/l]
[select]
      There seems to be some confusion here about what you are passing. @bind_values needs to be an array of values not an array of hashes or other structure and the Slice is how the returned data is handled. Me thinks that your code needs to be more like 
      my @param = <array of values to pass TO database>;
my $sql = <some SQL with placeholders = ? to take values>;
my $array_ref = $dbh->selectall_arrayref($sql,undef,@param);

      [download]
      If you need to run the query for multiple sets of parameters you are better off preparing the SQL and then fetching the data multiple times with each set of parameters. 
      my $dbh = <create database handle>;
my $sth = $dbh->prepare("select * from table where col1=? and col2=?")
+;
...
@param = ("test1a","test1b");
$array_ref = $sth->selectall_arrayref($sth,undef,@param);
...
@param = ("test2a","test2b);
$array_ref = $sth->selectall_arrayref($sth,undef,@param);
...

      [download]
      The use of statement handle in the selectall_arrayref is not something I've used yet but is in the DBI docs.
[reply]
[d/l]
[select]
      my $sth = $dbh->prepare($SQLQueryString);
my $array_ref = $dbh->selectall_arrayref( $SQLQueryString, { Slice => 
+{} }, @SQLvars );

      [download]
      First of all, you are preparing a statement handle, and then not using it (but using the database handle instead). Second, DBI does not expect named parametres (at least the way you're writing your placeholders), nor will that function accept an array of hashrefs. Instead, something like this would work: 
      $aref = $dbh->selectall_arrayref($sql, {stuff => 'here'}, 'TESTA1', 'T
+ESTA2', 'TESTA3');

      [download]
[reply]
[d/l]
[select]
        Just wanted to amend that, since you seem to be confused between the database handle functions and the statement handle functions, this would be the equivalent written using the sth functions: 
        $sth = $dbh->prepare($sql);
$sth->execute('TESTA1', 'TESTA2', 'TESTA3');
$aref = $sth->fetchall_arrayref({stuff => here});

        [download]
        (the database handle functions offer the do() and select*() shortcuts for doing similar things, although they are not as efficient in some cases)
[reply]
[d/l]
Re^2: DBI and arrays
by Anonymous Monk on Jan 17, 2012 at 11:44 UTC
    Thanks I'll give this a shot, I didn't intend to insult the docs for dbi, just my inability to understand them
[reply]

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