diff --git a/src/main/java/it/inaf/oats/vospace/persistence/NodeDAO.java b/src/main/java/it/inaf/oats/vospace/persistence/NodeDAO.java
index d8d05985732b2b2ed86997c19bee597280ff1b82..96f81dd2b8530f71f317f58e9d144a51113dd6f0 100644
--- a/src/main/java/it/inaf/oats/vospace/persistence/NodeDAO.java
+++ b/src/main/java/it/inaf/oats/vospace/persistence/NodeDAO.java
@@ -73,11 +73,11 @@ public class NodeDAO {
             int i = 0;
             ps.setString(++i, NodeUtils.getNodeName(myNode));
             ps.setBoolean(++i, NodeUtils.getIsBusy(myNode));
-            ps.setString(++i, NodeProperties.getPropertiesStringByURI(myNode, NodeProperties.getPropertyURI("creator")));
-            ps.setString(++i, NodeProperties.getPropertiesStringByURI(myNode, NodeProperties.getPropertyURI("creator")));
-            ps.setArray(++i, fromPropertyToArray(ps, NodeProperties.getPropertiesStringByURI(myNode, NodeProperties.getPropertyURI("groupread"))));
-            ps.setArray(++i, fromPropertyToArray(ps, NodeProperties.getPropertiesStringByURI(myNode, NodeProperties.getPropertyURI("groupwrite"))));
-            ps.setBoolean(++i, Boolean.valueOf(NodeProperties.getPropertiesStringByURI(myNode, NodeProperties.getPropertyURI("publicread"))));
+            ps.setString(++i, NodeProperties.getStandardNodePropertyByName(myNode, "creator"));
+            ps.setString(++i, NodeProperties.getStandardNodePropertyByName(myNode, "creator"));
+            ps.setArray(++i, fromPropertyToArray(ps, NodeProperties.getStandardNodePropertyByName(myNode, "groupread")));
+            ps.setArray(++i, fromPropertyToArray(ps, NodeProperties.getStandardNodePropertyByName(myNode, "groupwrite")));
+            ps.setBoolean(++i, Boolean.valueOf(NodeProperties.getStandardNodePropertyByName(myNode, "publicread")));
             ps.setObject(++i, paths.get(0).path, Types.OTHER);
             ps.setObject(++i, paths.get(0).relativePath, Types.OTHER);
             ps.setObject(++i, NodeUtils.getDbNodeType(myNode), Types.OTHER);
@@ -176,10 +176,10 @@ public class NodeDAO {
         jdbcTemplate.update(conn -> {
             PreparedStatement ps = conn.prepareStatement(sb.toString());
             int i = 0;
-            ps.setString(++i, NodeProperties.getPropertiesStringByURI(newNode, NodeProperties.getPropertyURI("creator")));
-            ps.setArray(++i, fromPropertyToArray(ps, NodeProperties.getPropertiesStringByURI(newNode, NodeProperties.getPropertyURI("groupread"))));
-            ps.setArray(++i, fromPropertyToArray(ps, NodeProperties.getPropertiesStringByURI(newNode, NodeProperties.getPropertyURI("groupwrite"))));
-            ps.setBoolean(++i, Boolean.valueOf(NodeProperties.getPropertiesStringByURI(newNode, NodeProperties.getPropertyURI("publicread"))));
+            ps.setString(++i, NodeProperties.getNodePropertyByURI(newNode, NodeProperties.CREATOR_URI));
+            ps.setArray(++i, fromPropertyToArray(ps, NodeProperties.getNodePropertyByURI(newNode, NodeProperties.GROUP_READ_URI)));
+            ps.setArray(++i, fromPropertyToArray(ps, NodeProperties.getNodePropertyByURI(newNode, NodeProperties.GROUP_WRITE_URI)));
+            ps.setBoolean(++i, Boolean.valueOf(NodeProperties.getNodePropertyByURI(newNode, NodeProperties.PUBLIC_READ_URI)));
             ps.setString(++i, paths.get(0).getPath());
             return ps;
         });
@@ -255,25 +255,25 @@ public class NodeDAO {
 
         List<Property> properties = new ArrayList<>();
 
-        addProperty(NodeProperties.getPropertyURI("length"), rs.getString("content_length"),
+        addProperty(NodeProperties.LENGTH_URI, rs.getString("content_length"),
                 properties);
 
-        addProperty(NodeProperties.getPropertyURI("btime"), rs.getString("created_on"),
+        addProperty(NodeProperties.INITIAL_CREATION_TIME_URI, rs.getString("created_on"),
                 properties);
 
-        addProperty(NodeProperties.getPropertyURI("creator"), rs.getString("creator_id"),
+        addProperty(NodeProperties.CREATOR_URI, rs.getString("creator_id"),
                 properties);
 
-        addProperty(NodeProperties.getPropertyURI("mtime"), rs.getString("last_modified"),
+        addProperty(NodeProperties.MODIFICATION_TIME_URI, rs.getString("last_modified"),
                 properties);
 
-        addProperty(NodeProperties.getPropertyURI("groupread"), getGroupsString(rs, "group_read"),
+        addProperty(NodeProperties.GROUP_READ_URI, getGroupsString(rs, "group_read"),
                 properties);
 
-        addProperty(NodeProperties.getPropertyURI("groupwrite"), getGroupsString(rs, "group_write"),
+        addProperty(NodeProperties.GROUP_WRITE_URI, getGroupsString(rs, "group_write"),
                 properties);
 
-        addProperty(NodeProperties.getPropertyURI("publicread"), String.valueOf(rs.getBoolean("is_public")),
+        addProperty(NodeProperties.PUBLIC_READ_URI, String.valueOf(rs.getBoolean("is_public")),
                 properties);
 
         addProperty("urn:async_trans", String.valueOf(rs.getBoolean("async_trans")),