/** @ODMDocument */
class Stat
{
    /** @ODMId(strategy="NONE", type="int") */
    private $id;

    /** @ODMField(type="string") */
    private $period;

    /** @ODMReferenceOne(targetDocument="Player") */
    private $player;

    /** @ODMField(type="string") @ODMIndex */
    private $statType;

$stat = new DocumentsStat();

$stat->setId(1);
$stat->setPlayer($player);
$stat->setPeriod(1);
$stat->setStatType('goal');

$dm->persist($stat);
$dm->flush();

/**
 * @ODMDocument
 * @ODMIndexes({
 *   @ODMIndex(keys={"statType"="asc"}),
 *   @ODMUniqueIndex(keys={"period"="asc"})//For example unique index
 * })
 */
class Stat
{
}