diff --git a/src/main/java/org/gcube/informationsystem/resourceregistry/instances/base/ElementManagement.java b/src/main/java/org/gcube/informationsystem/resourceregistry/instances/base/ElementManagement.java
index bec8e5d..5ed2ff4 100644
--- a/src/main/java/org/gcube/informationsystem/resourceregistry/instances/base/ElementManagement.java
+++ b/src/main/java/org/gcube/informationsystem/resourceregistry/instances/base/ElementManagement.java
@@ -513,14 +513,14 @@ public abstract class ElementManagement<El extends OElement> {
 				element = internalCreate();
 			}
 			
+			sanityCheck(null);
+			
 			oDatabaseDocument.commit();
 			
 			if(update) {
 				setReload(true);
 			}
 			
-			sanityCheck(null);
-			
 			// TODO Notify to subscriptionNotification
 			
 			return serializeAsJsonNode().toString();
@@ -556,10 +556,10 @@ public abstract class ElementManagement<El extends OElement> {
 			
 			element = internalCreate();
 			
-			oDatabaseDocument.commit();
-			
 			sanityCheck(null);
 			
+			oDatabaseDocument.commit();
+			
 			// TODO Notify to subscriptionNotification
 			
 			return serializeAsJsonNode().toString();
@@ -621,12 +621,12 @@ public abstract class ElementManagement<El extends OElement> {
 			
 			element = internalUpdate();
 			
+			sanityCheck(null);
+			
 			oDatabaseDocument.commit();
 			
 			setReload(true);
 			
-			sanityCheck(null);
-			
 			// TODO Notify to subscriptionNotification
 			
 			return serializeAsJsonNode().toString();
diff --git a/src/main/java/org/gcube/informationsystem/resourceregistry/instances/model/entities/ResourceManagement.java b/src/main/java/org/gcube/informationsystem/resourceregistry/instances/model/entities/ResourceManagement.java
index f174f10..8fec800 100644
--- a/src/main/java/org/gcube/informationsystem/resourceregistry/instances/model/entities/ResourceManagement.java
+++ b/src/main/java/org/gcube/informationsystem/resourceregistry/instances/model/entities/ResourceManagement.java
@@ -338,9 +338,11 @@ public class ResourceManagement extends EntityManagement<Resource> {
 		ResourceType resourceType = (ResourceType) cachedType.getType();
 		
 		List<LinkedEntity> linkedEntities = resourceType.getFacets();
-		for(LinkedEntity linkedEntity : linkedEntities) {
-			if(linkedEntity.getMin()>0 || linkedEntity.getMax()>0) {
-				constraints.add(linkedEntity);
+		if(linkedEntities!=null) {
+			for(LinkedEntity linkedEntity : linkedEntities) {
+				if(linkedEntity.getMin()>0 || (linkedEntity.getMax()!=null && linkedEntity.getMax()>0)) {
+					constraints.add(linkedEntity);
+				}
 			}
 		}
 		
@@ -352,9 +354,11 @@ public class ResourceManagement extends EntityManagement<Resource> {
 			
 			ResourceType resourceSuperType = (ResourceType) cachedSuperType.getType();
 			List<LinkedEntity> linkedEnt = resourceSuperType.getFacets();
-			for(LinkedEntity linkedEntity : linkedEnt) {
-				if(linkedEntity.getMin()>0 || linkedEntity.getMax()>0) {
-					constraints.add(linkedEntity);
+			if(linkedEnt!=null) {
+				for(LinkedEntity linkedEntity : linkedEnt) {
+					if(linkedEntity.getMin()>0 || (linkedEntity.getMax()!=null && linkedEntity.getMax()>0)) {
+						constraints.add(linkedEntity);
+					}
 				}
 			}
 		}
@@ -377,6 +381,9 @@ public class ResourceManagement extends EntityManagement<Resource> {
 		stringBuffer.append(". Found ");
 		stringBuffer.append(occurrence);
 		stringBuffer.append(" instances");
+		stringBuffer.append(". The constraint has been defined by ");
+		stringBuffer.append(linkedEntity.getSource());
+		stringBuffer.append(" type.");
 		return stringBuffer.toString();
 	}
 	
@@ -415,7 +422,7 @@ public class ResourceManagement extends EntityManagement<Resource> {
 	
 	@Override
 	public void sanityCheck(Map<UUID, JsonNode> expectedInstances) throws SchemaViolationException, ResourceRegistryException {
-		JsonNode resourceInstance = serializeAsJsonNode().deepCopy();
+		JsonNode resourceInstance = createCompleteJsonNode();
 		
 		TypesCache typesCache = TypesCache.getInstance();
 		
@@ -489,8 +496,8 @@ public class ResourceManagement extends EntityManagement<Resource> {
 				throw new SchemaViolationException(message);
 			}
 			
-			int max = linkedEntity.getMax();
-			if(max>0 && satisfiedTimes>max) {
+			Integer max = linkedEntity.getMax();
+			if((max!=null && max>0) && satisfiedTimes>max) {
 				String message = constraintNotSatisfiedErrorMessage(linkedEntity, satisfiedTimes);
 				throw new SchemaViolationException(message);
 			}
diff --git a/src/test/java/org/gcube/informationsystem/resourceregistry/instances/ERManagementTest.java b/src/test/java/org/gcube/informationsystem/resourceregistry/instances/ERManagementTest.java
index dbb9640..939bcd5 100644
--- a/src/test/java/org/gcube/informationsystem/resourceregistry/instances/ERManagementTest.java
+++ b/src/test/java/org/gcube/informationsystem/resourceregistry/instances/ERManagementTest.java
@@ -34,6 +34,7 @@ import org.gcube.informationsystem.resourceregistry.ContextTest;
 import org.gcube.informationsystem.resourceregistry.api.exceptions.ResourceRegistryException;
 import org.gcube.informationsystem.resourceregistry.api.exceptions.entity.facet.FacetNotFoundException;
 import org.gcube.informationsystem.resourceregistry.api.exceptions.query.InvalidQueryException;
+import org.gcube.informationsystem.resourceregistry.api.exceptions.schema.SchemaViolationException;
 import org.gcube.informationsystem.resourceregistry.instances.base.ElementManagementUtility;
 import org.gcube.informationsystem.resourceregistry.instances.model.entities.FacetManagement;
 import org.gcube.informationsystem.resourceregistry.instances.model.entities.ResourceManagement;
@@ -167,7 +168,7 @@ public class ERManagementTest extends ContextTest {
 		Assert.assertTrue(deleted);
 	}
 	
-	@Test
+	@Test(expected = SchemaViolationException.class)
 	public void testCreateRunningPlugin() throws Exception {
 		RunningPlugin runningPlugin = new RunningPluginImpl();
 
diff --git a/src/test/resources/logback-test.xml b/src/test/resources/logback-test.xml
index fd988d8..49e0744 100644
--- a/src/test/resources/logback-test.xml
+++ b/src/test/resources/logback-test.xml
@@ -14,7 +14,8 @@
   <logger name="org.gcube.informationsystem.types" level="INFO" />
   <logger name="org.gcube.informationsystem.resourceregistry.dbinitialization" level="INFO" />
   <logger name="org.gcube.informationsystem.utils.discovery" level="ERROR" />
-  
+  <logger name="org.gcube.informationsystem.resourceregistry.types" level="INFO" />
+   
   <root level="WARN">
     <appender-ref ref="STDOUT" />
   </root>