diff --git a/lib/taskana-core/src/main/java/pro/taskana/impl/AttachmentImpl.java b/lib/taskana-core/src/main/java/pro/taskana/impl/AttachmentImpl.java
index a58c5b257..b4c15b1a7 100644
--- a/lib/taskana-core/src/main/java/pro/taskana/impl/AttachmentImpl.java
+++ b/lib/taskana-core/src/main/java/pro/taskana/impl/AttachmentImpl.java
@@ -21,11 +21,6 @@ public class AttachmentImpl implements Attachment {
     private Timestamp modified;
     private Classification classification;
     private ObjectReference objectReference;
-    private String porCompany;
-    private String porSystem;
-    private String porSystemInstance;
-    private String porType;
-    private String porValue;
     private String channel;
     private Timestamp received;
     private Map<String, Object> customAttributes = Collections.emptyMap();;
@@ -119,46 +114,6 @@ public class AttachmentImpl implements Attachment {
         this.customAttributes = customAttributes;
     }
 
-    public String getPorCompany() {
-        return porCompany;
-    }
-
-    public void setPorCompany(String porCompany) {
-        this.porCompany = porCompany;
-    }
-
-    public String getPorSystem() {
-        return porSystem;
-    }
-
-    public void setPorSystem(String porSystem) {
-        this.porSystem = porSystem;
-    }
-
-    public String getPorSystemInstance() {
-        return porSystemInstance;
-    }
-
-    public void setPorSystemInstance(String porSystemInstance) {
-        this.porSystemInstance = porSystemInstance;
-    }
-
-    public String getPorType() {
-        return porType;
-    }
-
-    public void setPorType(String porType) {
-        this.porType = porType;
-    }
-
-    public String getPorValue() {
-        return porValue;
-    }
-
-    public void setPorValue(String porValue) {
-        this.porValue = porValue;
-    }
-
     @Override
     public String toString() {
         StringBuilder builder = new StringBuilder();
@@ -172,16 +127,6 @@ public class AttachmentImpl implements Attachment {
         builder.append(modified);
         builder.append(", classification=");
         builder.append(classification);
-        builder.append(", porCompany=");
-        builder.append(porCompany);
-        builder.append(", porSystem=");
-        builder.append(porSystem);
-        builder.append(", porSystemInstance=");
-        builder.append(porSystemInstance);
-        builder.append(", porType=");
-        builder.append(porType);
-        builder.append(", porValue=");
-        builder.append(porValue);
         builder.append(", objectReference=");
         builder.append(objectReference);
         builder.append(", channel=");
diff --git a/lib/taskana-core/src/main/java/pro/taskana/impl/TaskImpl.java b/lib/taskana-core/src/main/java/pro/taskana/impl/TaskImpl.java
index cf2628d5c..4625b08a9 100644
--- a/lib/taskana-core/src/main/java/pro/taskana/impl/TaskImpl.java
+++ b/lib/taskana-core/src/main/java/pro/taskana/impl/TaskImpl.java
@@ -41,11 +41,6 @@ public class TaskImpl implements Task {
     private boolean isTransferred;
     // All objects have to be serializable
     private Map<String, Object> customAttributes = Collections.emptyMap();
-    private String porCompany;          // auxiliary field needed to avoid 2nd query for primaryObjRef in TaskMapper
-    private String porSystem;           // auxiliary field needed to avoid 2nd query for primaryObjRef in TaskMapper
-    private String porSystemInstance;   // auxiliary field needed to avoid 2nd query for primaryObjRef in TaskMapper
-    private String porType;             // auxiliary field needed to avoid 2nd query for primaryObjRef in TaskMapper
-    private String porValue;            // auxiliary field needed to avoid 2nd query for primaryObjRef in TaskMapper
     private List<Attachment> attachments;
     private String custom1;
     private String custom2;
@@ -392,46 +387,6 @@ public class TaskImpl implements Task {
         this.classification = classification;
     }
 
-    public String getPorCompany() {
-        return porCompany;
-    }
-
-    public void setPorCompany(String porCompany) {
-        this.porCompany = porCompany;
-    }
-
-    public String getPorSystem() {
-        return porSystem;
-    }
-
-    public void setPorSystem(String porSystem) {
-        this.porSystem = porSystem;
-    }
-
-    public String getPorSystemInstance() {
-        return porSystemInstance;
-    }
-
-    public void setPorSystemInstance(String porSystemInstance) {
-        this.porSystemInstance = porSystemInstance;
-    }
-
-    public String getPorType() {
-        return porType;
-    }
-
-    public void setPorType(String porType) {
-        this.porType = porType;
-    }
-
-    public String getPorValue() {
-        return porValue;
-    }
-
-    public void setPorValue(String porValue) {
-        this.porValue = porValue;
-    }
-
     @Override
     public String toString() {
         StringBuilder builder = new StringBuilder();
@@ -481,16 +436,6 @@ public class TaskImpl implements Task {
         builder.append(isTransferred);
         builder.append(", customAttributes=");
         builder.append(customAttributes);
-        builder.append(", porCompany=");
-        builder.append(porCompany);
-        builder.append(", porSystem=");
-        builder.append(porSystem);
-        builder.append(", porSystemInstance=");
-        builder.append(porSystemInstance);
-        builder.append(", porType=");
-        builder.append(porType);
-        builder.append(", porValue=");
-        builder.append(porValue);
         builder.append(", attachments=");
         builder.append(attachments);
         builder.append(", custom1=");
diff --git a/lib/taskana-core/src/main/java/pro/taskana/impl/TaskQueryImpl.java b/lib/taskana-core/src/main/java/pro/taskana/impl/TaskQueryImpl.java
index 14458647d..ec420b212 100644
--- a/lib/taskana-core/src/main/java/pro/taskana/impl/TaskQueryImpl.java
+++ b/lib/taskana-core/src/main/java/pro/taskana/impl/TaskQueryImpl.java
@@ -203,7 +203,6 @@ public class TaskQueryImpl implements TaskQuery {
             checkAuthorization();
             List<TaskImpl> tasks = taskanaEngineImpl.getSqlSession().selectList(LINK_TO_MAPPER, this);
             for (TaskImpl taskImpl : tasks) {
-                TaskServiceImpl.setPrimaryObjRef(taskImpl);
                 try {
                     Classification classification = this.classificationService.getClassificationByTask(taskImpl);
                     taskImpl.setClassification(classification);
@@ -234,7 +233,6 @@ public class TaskQueryImpl implements TaskQuery {
             RowBounds rowBounds = new RowBounds(offset, limit);
             List<TaskImpl> tasks = taskanaEngineImpl.getSqlSession().selectList(LINK_TO_MAPPER, this, rowBounds);
             for (TaskImpl taskImpl : tasks) {
-                TaskServiceImpl.setPrimaryObjRef(taskImpl);
                 try {
                     Classification classification = this.classificationService.getClassificationByTask(taskImpl);
                     taskImpl.setClassification(classification);
@@ -263,7 +261,6 @@ public class TaskQueryImpl implements TaskQuery {
             taskanaEngineImpl.openConnection();
             checkAuthorization();
             taskImpl = taskanaEngineImpl.getSqlSession().selectOne(LINK_TO_MAPPER, this);
-            TaskServiceImpl.setPrimaryObjRef(taskImpl);
             try {
                 Classification classification = this.classificationService.getClassificationByTask(taskImpl);
                 taskImpl.setClassification(classification);
diff --git a/lib/taskana-core/src/main/java/pro/taskana/impl/TaskServiceImpl.java b/lib/taskana-core/src/main/java/pro/taskana/impl/TaskServiceImpl.java
index 8696f0a28..aabc78b07 100644
--- a/lib/taskana-core/src/main/java/pro/taskana/impl/TaskServiceImpl.java
+++ b/lib/taskana-core/src/main/java/pro/taskana/impl/TaskServiceImpl.java
@@ -202,10 +202,7 @@ public class TaskServiceImpl implements TaskService {
             taskanaEngineImpl.openConnection();
             result = taskMapper.findById(id);
             if (result != null) {
-                setPrimaryObjRef(result);
-                List<Attachment> attachments = setAttachmentObjRef(
-                    attachmentMapper.findAttachmentsByTaskId(result.getId()));
-                result.setAttachments(attachments);
+                setAttachments(result);
                 Classification classification;
                 try {
                     classification = this.classificationService.getClassificationByTask(result);
@@ -305,7 +302,6 @@ public class TaskServiceImpl implements TaskService {
             workbasketService.checkAuthorization(workbasketKey, WorkbasketAuthorization.READ);
             List<TaskImpl> tasks = taskMapper.findTasksByWorkbasketIdAndState(workbasketKey, taskState);
             tasks.stream().forEach(t -> {
-                TaskServiceImpl.setPrimaryObjRef(t);
                 results.add(t);
             });
         } finally {
@@ -444,31 +440,15 @@ public class TaskServiceImpl implements TaskService {
         return new AttachmentImpl();
     }
 
-    static void setPrimaryObjRef(TaskImpl task) {
-        ObjectReference objRef = new ObjectReference();
-        objRef.setCompany(task.getPorCompany());
-        objRef.setSystem(task.getPorSystem());
-        objRef.setSystemInstance(task.getPorSystemInstance());
-        objRef.setType(task.getPorType());
-        objRef.setValue(task.getPorValue());
-        task.setPrimaryObjRef(objRef);
-    }
-
-    private List<Attachment> setAttachmentObjRef(List<AttachmentImpl> attachments) {
-        List<Attachment> results = new ArrayList<>();
-        if (attachments != null && !attachments.isEmpty()) {
-            for (AttachmentImpl attachment : attachments) {
-                ObjectReference objRef = new ObjectReference();
-                objRef.setCompany(attachment.getPorCompany());
-                objRef.setSystem(attachment.getPorSystem());
-                objRef.setSystemInstance(attachment.getPorSystemInstance());
-                objRef.setType(attachment.getPorType());
-                objRef.setValue(attachment.getPorValue());
-                attachment.setObjectReference(objRef);
-                results.add(attachment);
+    private void setAttachments(TaskImpl result) {
+        List<AttachmentImpl> attachmentImpls = attachmentMapper.findAttachmentsByTaskId(result.getId());
+        List<Attachment> attachments = new ArrayList<>();
+        if (attachmentImpls != null && !attachmentImpls.isEmpty()) {
+            for (AttachmentImpl attImpl : attachmentImpls) {
+                attachments.add(attImpl);
             }
         }
-        return results;
+        result.setAttachments(attachments);
     }
 
     private void validateObjectReference(ObjectReference objRef, String objRefType, String objName)
diff --git a/lib/taskana-core/src/main/java/pro/taskana/model/mappings/AttachmentMapper.java b/lib/taskana-core/src/main/java/pro/taskana/model/mappings/AttachmentMapper.java
index 1695df301..b750b3338 100644
--- a/lib/taskana-core/src/main/java/pro/taskana/model/mappings/AttachmentMapper.java
+++ b/lib/taskana-core/src/main/java/pro/taskana/model/mappings/AttachmentMapper.java
@@ -37,11 +37,11 @@ public interface AttachmentMapper {
         @Result(property = "modified", column = "MODIFIED"),
         @Result(property = "classification", column = "CLASSIFICATION_KEY", javaType = Classification.class,
             one = @One(select = CLASSIFICATION_FINDBYID)),
-        @Result(property = "porCompany", column = "REF_COMPANY"),
-        @Result(property = "porSystem", column = "REF_SYSTEM"),
-        @Result(property = "porSystemInstance", column = "REF_INSTANCE"),
-        @Result(property = "porType", column = "REF_TYPE"),
-        @Result(property = "porValue", column = "REF_VALUE"),
+        @Result(property = "objectReference.company", column = "REF_COMPANY"),
+        @Result(property = "objectReference.system", column = "REF_SYSTEM"),
+        @Result(property = "objectReference.systemInstance", column = "REF_INSTANCE"),
+        @Result(property = "objectReference.type", column = "REF_TYPE"),
+        @Result(property = "objectReference.value", column = "REF_VALUE"),
         @Result(property = "channel", column = "CHANNEL"),
         @Result(property = "received", column = "RECEIVED"),
         @Result(property = "customAttributes", column = "CUSTOM_ATTRIBUTES", jdbcType = JdbcType.BLOB,
diff --git a/lib/taskana-core/src/main/java/pro/taskana/model/mappings/QueryMapper.java b/lib/taskana-core/src/main/java/pro/taskana/model/mappings/QueryMapper.java
index 53dad68cd..4a1af3413 100644
--- a/lib/taskana-core/src/main/java/pro/taskana/model/mappings/QueryMapper.java
+++ b/lib/taskana-core/src/main/java/pro/taskana/model/mappings/QueryMapper.java
@@ -51,7 +51,7 @@ public interface QueryMapper {
         + "<if test='customFields != null'>AND (t.CUSTOM_1 IN(<foreach item='item' collection='customFields' separator=',' >#{item}</foreach>) OR t.CUSTOM_2 IN(<foreach item='item' collection='customFields' separator=',' >#{item}</foreach>) OR t.CUSTOM_3 IN(<foreach item='item' collection='customFields' separator=',' >#{item}</foreach>) OR t.CUSTOM_4 IN(<foreach item='item' collection='customFields' separator=',' >#{item}</foreach>) OR t.CUSTOM_5 IN(<foreach item='item' collection='customFields' separator=',' >#{item}</foreach>) OR t.CUSTOM_6 IN(<foreach item='item' collection='customFields' separator=',' >#{item}</foreach>) OR t.CUSTOM_7 IN(<foreach item='item' collection='customFields' separator=',' >#{item}</foreach>) OR t.CUSTOM_8 IN(<foreach item='item' collection='customFields' separator=',' >#{item}</foreach>) OR t.CUSTOM_9 IN(<foreach item='item' collection='customFields' separator=',' >#{item}</foreach>) OR t.CUSTOM_10 IN(<foreach item='item' collection='customFields' separator=',' >#{item}</foreach>))</if> "
         + "</where>"
         + "</script>")
-    @Results(value = { @Result(property = "id", column = "ID"),
+    @Results(value = {@Result(property = "id", column = "ID"),
         @Result(property = "created", column = "CREATED"),
         @Result(property = "claimed", column = "CLAIMED"),
         @Result(property = "completed", column = "COMPLETED"),
@@ -69,11 +69,11 @@ public interface QueryMapper {
         @Result(property = "businessProcessId", column = "BUSINESS_PROCESS_ID"),
         @Result(property = "parentBusinessProcessId", column = "PARENT_BUSINESS_PROCESS_ID"),
         @Result(property = "owner", column = "OWNER"),
-        @Result(property = "porCompany", column = "POR_COMPANY"),
-        @Result(property = "porSystem", column = "POR_SYSTEM"),
-        @Result(property = "porSystemInstance", column = "POR_INSTANCE"),
-        @Result(property = "porType", column = "POR_TYPE"),
-        @Result(property = "porValue", column = "POR_VALUE"),
+        @Result(property = "primaryObjRef.company", column = "POR_COMPANY"),
+        @Result(property = "primaryObjRef.system", column = "POR_SYSTEM"),
+        @Result(property = "primaryObjRef.systemInstance", column = "POR_INSTANCE"),
+        @Result(property = "primaryObjRef.type", column = "POR_TYPE"),
+        @Result(property = "primaryObjRef.value", column = "POR_VALUE"),
         @Result(property = "isRead", column = "IS_READ"),
         @Result(property = "isTransferred", column = "IS_TRANSFERRED"),
         @Result(property = "custom1", column = "CUSTOM_1"),
@@ -85,7 +85,7 @@ public interface QueryMapper {
         @Result(property = "custom7", column = "CUSTOM_7"),
         @Result(property = "custom8", column = "CUSTOM_8"),
         @Result(property = "custom9", column = "CUSTOM_9"),
-        @Result(property = "custom10", column = "CUSTOM_10") })
+        @Result(property = "custom10", column = "CUSTOM_10")})
     List<TaskImpl> queryTasks(TaskQueryImpl taskQuery);
 
     @Select("<script>SELECT ID, KEY, PARENT_CLASSIFICATION_KEY, CATEGORY, TYPE, DOMAIN, VALID_IN_DOMAIN, CREATED, NAME, DESCRIPTION, PRIORITY, SERVICE_LEVEL, APPLICATION_ENTRY_POINT, CUSTOM_1, CUSTOM_2, CUSTOM_3, CUSTOM_4, CUSTOM_5, CUSTOM_6, CUSTOM_7, CUSTOM_8, VALID_FROM, VALID_UNTIL "
@@ -108,13 +108,13 @@ public interface QueryMapper {
         + "<if test='validUntil != null'>AND VALID_UNTIL IN(<foreach item='item' collection='validUntil' separator=',' >#{item}</foreach>)</if> "
         + "</where>"
         + "</script>")
-    @Results({ @Result(property = "id", column = "ID"),
+    @Results({@Result(property = "id", column = "ID"),
         @Result(property = "key", column = "KEY"),
         @Result(property = "category", column = "CATEGORY"),
         @Result(property = "type", column = "TYPE"),
         @Result(property = "domain", column = "DOMAIN"),
         @Result(property = "name", column = "NAME"),
-        @Result(property = "validUntil", column = "VALID_UNTIL") })
+       @Result(property = "validUntil", column = "VALID_UNTIL")})
     List<ClassificationSummaryImpl> queryClassification(ClassificationQueryImpl classificationQuery);
 
     @Select("<script>SELECT ID, COMPANY, SYSTEM, SYSTEM_INSTANCE, TYPE, VALUE "
@@ -133,7 +133,7 @@ public interface QueryMapper {
         @Result(property = "system", column = "SYSTEM"),
         @Result(property = "systemInstance", column = "SYSTEM_INSTANCE"),
         @Result(property = "type", column = "TYPE"),
-        @Result(property = "value", column = "VALUE") })
+        @Result(property = "value", column = "VALUE")})
     List<ObjectReference> queryObjectReference(ObjectReferenceQueryImpl objectReference);
 
     @Select("<script>SELECT w.ID, w.KEY, w.NAME, w.DOMAIN, W.TYPE, w.DESCRIPTION, w.OWNER, w.ORG_LEVEL_1, w.ORG_LEVEL_2, w.ORG_LEVEL_3, w.ORG_LEVEL_4 from WORKBASKET w "
@@ -178,6 +178,6 @@ public interface QueryMapper {
         @Result(property = "orgLevel1", column = "ORG_LEVEL_1"),
         @Result(property = "orgLevel2", column = "ORG_LEVEL_2"),
         @Result(property = "orgLevel3", column = "ORG_LEVEL_3"),
-        @Result(property = "orgLevel4", column = "ORG_LEVEL_4") })
+        @Result(property = "orgLevel4", column = "ORG_LEVEL_4")})
     List<WorkbasketSummary> queryWorkbasket(WorkbasketQueryImpl workbasketQuery);
 }
diff --git a/lib/taskana-core/src/main/java/pro/taskana/model/mappings/TaskMapper.java b/lib/taskana-core/src/main/java/pro/taskana/model/mappings/TaskMapper.java
index 84e1e4a0a..5740d7907 100644
--- a/lib/taskana-core/src/main/java/pro/taskana/model/mappings/TaskMapper.java
+++ b/lib/taskana-core/src/main/java/pro/taskana/model/mappings/TaskMapper.java
@@ -53,11 +53,11 @@ public interface TaskMapper {
         @Result(property = "businessProcessId", column = "BUSINESS_PROCESS_ID"),
         @Result(property = "parentBusinessProcessId", column = "PARENT_BUSINESS_PROCESS_ID"),
         @Result(property = "owner", column = "OWNER"),
-        @Result(property = "porCompany", column = "POR_COMPANY"),
-        @Result(property = "porSystem", column = "POR_SYSTEM"),
-        @Result(property = "porSystemInstance", column = "POR_INSTANCE"),
-        @Result(property = "porType", column = "POR_TYPE"),
-        @Result(property = "porValue", column = "POR_VALUE"),
+        @Result(property = "primaryObjRef.company", column = "POR_COMPANY"),
+        @Result(property = "primaryObjRef.system", column = "POR_SYSTEM"),
+        @Result(property = "primaryObjRef.systemInstance", column = "POR_INSTANCE"),
+        @Result(property = "primaryObjRef.type", column = "POR_TYPE"),
+        @Result(property = "primaryObjRef.value", column = "POR_VALUE"),
         @Result(property = "isRead", column = "IS_READ"),
         @Result(property = "isTransferred", column = "IS_TRANSFERRED"),
         @Result(property = "customAttributes", column = "CUSTOM_ATTRIBUTES", jdbcType = JdbcType.BLOB,
@@ -75,9 +75,9 @@ public interface TaskMapper {
     })
     TaskImpl findById(@Param("id") String id);
 
-    @Results({ @Result(column = "DUE_DATE", property = "due"),
+    @Results({@Result(column = "DUE_DATE", property = "due"),
         @Result(column = "WORKBASKET_KEY", property = "workbasketKey"),
-        @Result(column = "counter", property = "taskCounter") })
+        @Result(column = "counter", property = "taskCounter")})
     List<DueWorkbasketCounter> getTaskCountByWorkbasketIdAndDaysInPastAndState(@Param("fromDate") Date fromDate,
         @Param("status") List<TaskState> states);
 
@@ -115,11 +115,11 @@ public interface TaskMapper {
             one = @One(select = CLASSIFICATION_FINDBYKEYANDDOMAIN)),
         @Result(property = "domain", column = "DOMAIN"),
         @Result(property = "owner", column = "OWNER"),
-        @Result(property = "porCompany", column = "POR_COMPANY"),
-        @Result(property = "porSystem", column = "POR_SYSTEM"),
-        @Result(property = "porSystemInstance", column = "POR_INSTANCE"),
-        @Result(property = "porType", column = "POR_TYPE"),
-        @Result(property = "porValue", column = "POR_VALUE"),
+        @Result(property = "primaryObjRef.company", column = "POR_COMPANY"),
+        @Result(property = "primaryObjRef.system", column = "POR_SYSTEM"),
+        @Result(property = "primaryObjRef.systemInstance", column = "POR_INSTANCE"),
+        @Result(property = "primaryObjRef.type", column = "POR_TYPE"),
+        @Result(property = "primaryObjRef.value", column = "POR_VALUE"),
         @Result(property = "isRead", column = "IS_READ"),
         @Result(property = "isTransferred", column = "IS_TRANSFERRED"),
         @Result(property = "customAttributes", column = "CUSTOM_ATTRIBUTES", jdbcType = JdbcType.BLOB,
@@ -133,7 +133,7 @@ public interface TaskMapper {
         @Result(property = "custom7", column = "CUSTOM_7"),
         @Result(property = "custom8", column = "CUSTOM_8"),
         @Result(property = "custom9", column = "CUSTOM_9"),
-        @Result(property = "custom10", column = "CUSTOM_10") })
+        @Result(property = "custom10", column = "CUSTOM_10")})
     List<TaskImpl> findTasksByWorkbasketIdAndState(@Param("workbasketKey") String workbasketKey,
         @Param("taskState") TaskState taskState);