Retrieving specific document using explicit index lookup

Question

The best way to retrieve a specific document seems to be using XmlContainer::getDocument, thus using the default index.
However, I may not have the document name, but instead an ID I have defined a unique index for.
Of course, I can use the XQuery interface to retrieve the document, and it's fast.
It's faster, though, to directly use an index. I can use XmlContainer::lookupIndex in order to do this; it takes an optional parameter "value", and the documentation for 2.3.10 says: "Provides the value to which equality indices must be equal. This parameter is required when returning documents on equality indices, and it is ignored for all other types of indices."
However, the documentation also says that XmlContainer::lookupIndex is deprecated, "in favor of using XmlManager::createIndexLookup and XmlIndexLookup::execute". That recommended approach does not seem to provide a way to look up a specific value. It seems I have to iterate over the index, which is not what I want. Am I missing something?
Michael Ludwig

Answer 1

George,
thanks a lot - should have found this myself, I guess. Working example following:
use strict;
use warnings;
use Sleepycat::DbXml 'simple';
my $id = shift or die "usage: $0 <ID>\n";
my $contfile = $ENV{HOME} . '/dbenv/tv.dbxml';
my $iuri = ''; my $iname = 'ID';
my $istrat = 'unique-node-attribute-equality-decimal';
eval {
    my $mgr = XmlManager->new;
    my $cont = $mgr->openContainer($contfile, Db::DB_RDONLY);
    my $sval = XmlValue->new(XmlValue::DECIMAL, $id);
    my $idx = $mgr->createIndexLookup($cont, $iuri, $iname, $istrat, $sval);
    my $ctx = $mgr->createQueryContext(
        XmlQueryContext::LiveValues,
        XmlQueryContext::Lazy);
    my $res = $idx->execute($ctx);
    while ($res->hasNext) {
        $res->next(my $val);
        print $val;
my $ex;
if ($ex = catch XmlException) {
    die join "\n", ref $ex, $ex->what,
        'Exception Code: ' . $ex->getExceptionCode,
        'DbErrno: ' . $ex->getDbErrno;
elsif ($ex = catch std::exception) { die join "\n", ref $ex, $ex->what }
elsif ($@)                         { die $@ }For an alternative approach using setLowBound(), apply the following diff:
12c12,13
<     my $idx = $mgr->createIndexLookup($cont, $iuri, $iname, $istrat, $sval);
my $idx = $mgr->createIndexLookup($cont, $iuri, $iname, $istrat);
$idx->setLowBound( $sval, XmlIndexLookup::EQ );Thanks,
Michael