diff --git a/src/main/java/org/wikitolearn/dao/MetadataDAO.java b/src/main/java/org/wikitolearn/dao/MetadataDAO.java
index 04bea59..a499165 100644
--- a/src/main/java/org/wikitolearn/dao/MetadataDAO.java
+++ b/src/main/java/org/wikitolearn/dao/MetadataDAO.java
@@ -1,52 +1,95 @@
 package org.wikitolearn.dao;
 
 import com.orientechnologies.orient.core.metadata.schema.OClass;
 import com.orientechnologies.orient.core.metadata.schema.OType;
 import com.orientechnologies.orient.core.sql.OCommandSQL;
 import com.sun.org.apache.xpath.internal.operations.Bool;
+import com.tinkerpop.blueprints.Direction;
+import com.tinkerpop.blueprints.Edge;
+import com.tinkerpop.blueprints.Vertex;
+import com.tinkerpop.blueprints.impls.orient.OrientGraph;
 import com.tinkerpop.blueprints.impls.orient.OrientGraphNoTx;
 import com.tinkerpop.blueprints.impls.orient.OrientVertex;
 import com.tinkerpop.blueprints.impls.orient.OrientVertexType;
 import org.springframework.stereotype.Repository;
+import org.wikitolearn.models.Process;
 
 import java.util.Date;
+import java.util.HashMap;
+import java.util.Map;
 
 /**
  * This class represents Metadata nodes in the DB. There is a unique Metadata node,
  * as a entrypoint, and a chain of Process nodes, saving some useful information at every
  * process in the rating engine. For example we can save the number of fetched pages or
  * saved user votes.
  * Created by valsdav on 21/03/17.
  */
 @Repository
 public class MetadataDAO extends GenericDAO {
 
+    private String metadataNodeID;
+
     /**
      * This method creates the classes Metadata and Process in the DB.
      * The Metadata node is the entrypoint for the chain of Processes, via the
      * edges LastProcess and PreviousProcess
      */
     @Override
     public void createDatabaseClass() {
         LOG.info("Creating DB classes for MetadataDAO...");
         OrientGraphNoTx graph = connection.getGraphNT();
         try{
             graph.createVertexType("Metadata",1);
             OrientVertexType processVertex = graph.createVertexType("Process",1);
             processVertex.createProperty("timestamp", OType.DATETIME).setMandatory(true);
             graph.createEdgeType("LastProcess");
             graph.createEdgeType("PreviousProcess");
+            graph.createEdgeType("SubProcess");
 
             //We want also to create the singleton node for Metadata.
             OrientVertex metadata_main = graph.addVertex("class:Metadata");
+            metadataNodeID = (String) metadata_main.getId();
             metadata_main.setProperty("creation_date", new Date());
         } catch( Exception e ) {
             LOG.error("Something went wrong during class creation. {}.", e.getMessage());
         } finally {
             graph.shutdown();
         }
     }
-    
+
+    /**
+     * This method insert a new Process on the top of the chain in the db.
+     * It creates the new link between the Metadata node and the Process.
+     * @param process Process to be inserted
+     * @return
+     */
+    public void addProcess(Process process){
+        LOG.info("Inserting process...");
+        OrientGraph graph = connection.getGraph();
+        try {
+            //getting last Process
+            Vertex metadataNode = graph.getVertex(metadataNodeID);
+            Edge lastProcessEdge = metadataNode.getEdges(Direction.OUT, "LastProcess").iterator().next();
+            Vertex lastProcess = lastProcessEdge.getVertex(Direction.OUT);
+            graph.removeEdge(lastProcessEdge);
+            //adding new Process
+            Map<String, Object> props = new HashMap<>();
+            props.put("timestamp", process.getTimestamp());
+            props.put("processType", process.getProcessType());
+            props.put("processResult", process.getProcessResult());
+            Vertex newProcess = graph.addVertex("class:Process", props);
+            //linking the node
+            metadataNode.addEdge("class:LastProcess", newProcess);
+            newProcess.addEdge("class:PreviousProcess", lastProcess);
+            graph.commit();
+        } catch (Exception e){
+            LOG.error("Something went wrong during the insertion of the process. {}.", e.getMessage());
+            graph.rollback();
+        } finally {
+            graph.shutdown();
+        }
+    }
 }
 
 
diff --git a/src/main/java/org/wikitolearn/models/Process.java b/src/main/java/org/wikitolearn/models/Process.java
index 0b31d03..631fbdc 100644
--- a/src/main/java/org/wikitolearn/models/Process.java
+++ b/src/main/java/org/wikitolearn/models/Process.java
@@ -1,56 +1,62 @@
 package org.wikitolearn.models;
 
 import java.util.Date;
 
 /**
  * This class represents a Process happened in the engine.
  * It has a definite type and can have different results. It is saved in the DB
  * as a Process vertex.
  * Created by valsdav on 21/03/17.
  */
 public class Process {
 
     private Date timestamp;
     private ProcessType processType;
     private ProcessResult processResult;
 
     public Process() {}
 
     public Process(Date timestamp, ProcessType processType, ProcessResult processResult) {
         this.timestamp = timestamp;
         this.processType = processType;
         this.processResult = processResult;
     }
 
+    public Process(ProcessType processType){
+        this.timestamp = new Date();
+        this.processType = processType;
+        this.processResult = ProcessResult.ONGOING;
+    }
+
     public Date getTimestamp() {
         return timestamp;
     }
 
     public void setTimestamp(Date timestamp) {
         this.timestamp = timestamp;
     }
 
     public ProcessType getProcessType() {
         return processType;
     }
 
     public void setProcessType(ProcessType processType) {
         this.processType = processType;
     }
 
     public ProcessResult getProcessResult() {
         return processResult;
     }
 
     public void setProcessResult(ProcessResult processResult) {
         this.processResult = processResult;
     }
 }
 
 enum ProcessType{
     INIT, FETCH, UPDATE_RANKING_PAGES, UPDATE_RANKING_USERS
 }
 
 enum ProcessResult{
-    DONE, ERROR, EXCEPTION
+    DONE, ERROR, EXCEPTION, ONGOING
 }
\ No newline at end of file