diff --git a/src/applications/harbormaster/storage/build/HarbormasterBuildArtifact.php b/src/applications/harbormaster/storage/build/HarbormasterBuildArtifact.php
index 0b195db88f..bb5f8382ba 100644
--- a/src/applications/harbormaster/storage/build/HarbormasterBuildArtifact.php
+++ b/src/applications/harbormaster/storage/build/HarbormasterBuildArtifact.php
@@ -1,137 +1,140 @@
 <?php
 
 final class HarbormasterBuildArtifact extends HarbormasterDAO
   implements PhabricatorPolicyInterface {
 
   protected $buildTargetPHID;
   protected $artifactType;
   protected $artifactIndex;
   protected $artifactKey;
   protected $artifactData = array();
 
   private $buildTarget = self::ATTACHABLE;
   private $artifactImplementation;
 
   public static function initializeNewBuildArtifact(
     HarbormasterBuildTarget $build_target) {
     return id(new HarbormasterBuildArtifact())
       ->attachBuildTarget($build_target)
       ->setBuildTargetPHID($build_target->getPHID());
   }
 
   protected function getConfiguration() {
     return array(
       self::CONFIG_AUX_PHID => true,
       self::CONFIG_SERIALIZATION => array(
         'artifactData' => self::SERIALIZATION_JSON,
       ),
       self::CONFIG_COLUMN_SCHEMA => array(
         'artifactType' => 'text32',
         'artifactIndex' => 'bytes12',
         'artifactKey' => 'text255',
       ),
       self::CONFIG_KEY_SCHEMA => array(
         'key_artifact' => array(
           'columns' => array('artifactType', 'artifactIndex'),
           'unique' => true,
         ),
         'key_garbagecollect' => array(
           'columns' => array('artifactType', 'dateCreated'),
         ),
+        'key_target' => array(
+          'columns' => array('buildTargetPHID', 'artifactType'),
+        ),
       ),
     ) + parent::getConfiguration();
   }
 
   public function generatePHID() {
     return PhabricatorPHID::generateNewPHID(
       HarbormasterBuildArtifactPHIDType::TYPECONST);
   }
 
   public function attachBuildTarget(HarbormasterBuildTarget $build_target) {
     $this->buildTarget = $build_target;
     return $this;
   }
 
   public function getBuildTarget() {
     return $this->assertAttached($this->buildTarget);
   }
 
   public function setArtifactKey($key) {
     $target = $this->getBuildTarget();
     $this->artifactIndex = self::getArtifactIndex($target, $key);
     $this->artifactKey = $key;
     return $this;
   }
 
   public static function getArtifactIndex(
     HarbormasterBuildTarget $target,
     $artifact_key) {
 
     $build = $target->getBuild();
 
     $parts = array(
       $build->getPHID(),
       $target->getBuildGeneration(),
       $artifact_key,
     );
     $parts = implode("\0", $parts);
 
     return PhabricatorHash::digestForIndex($parts);
   }
 
   public function releaseArtifact() {
     $impl = $this->getArtifactImplementation();
 
     if ($impl) {
       $impl->releaseArtifact(PhabricatorUser::getOmnipotentUser());
     }
 
     return null;
   }
 
   public function getArtifactImplementation() {
     if ($this->artifactImplementation === null) {
       $type = $this->getArtifactType();
       $impl = HarbormasterArtifact::getArtifactType($type);
       if (!$impl) {
         return null;
       }
 
       $impl = clone $impl;
       $impl->setBuildArtifact($this);
       $this->artifactImplementation = $impl;
     }
 
     return $this->artifactImplementation;
   }
 
 
   public function getProperty($key, $default = null) {
     return idx($this->artifactData, $key, $default);
   }
 
 
 /* -(  PhabricatorPolicyInterface  )----------------------------------------- */
 
 
   public function getCapabilities() {
     return array(
       PhabricatorPolicyCapability::CAN_VIEW,
     );
   }
 
   public function getPolicy($capability) {
     return $this->getBuildTarget()->getPolicy($capability);
   }
 
   public function hasAutomaticCapability($capability, PhabricatorUser $viewer) {
     return $this->getBuildTarget()->hasAutomaticCapability(
       $capability,
       $viewer);
   }
 
   public function describeAutomaticCapability($capability) {
     return pht('Users must be able to see a buildable to see its artifacts.');
   }
 
 }