diff --git a/src/main/java/org/gcube/informationsystem/resourceregistry/contexts/ContextUtility.java b/src/main/java/org/gcube/informationsystem/resourceregistry/contexts/ContextUtility.java
index 4955971..873f748 100644
--- a/src/main/java/org/gcube/informationsystem/resourceregistry/contexts/ContextUtility.java
+++ b/src/main/java/org/gcube/informationsystem/resourceregistry/contexts/ContextUtility.java
@@ -21,7 +21,6 @@ import org.gcube.informationsystem.resourceregistry.api.exceptions.context.Conte
 import org.gcube.informationsystem.resourceregistry.contexts.security.AdminSecurityContext;
 import org.gcube.informationsystem.resourceregistry.contexts.security.SecurityContext;
 import org.gcube.informationsystem.resourceregistry.contexts.security.SecurityContext.PermissionMode;
-import org.gcube.informationsystem.resourceregistry.dbinitialization.DatabaseEnvironment;
 import org.gcube.informationsystem.resourceregistry.instances.base.ElementManagementUtility;
 import org.gcube.informationsystem.resourceregistry.utils.Utility;
 import org.slf4j.Logger;
@@ -105,7 +104,7 @@ public class ContextUtility {
 	
 	public static AdminSecurityContext getAdminSecurityContext() throws ResourceRegistryException {
 		AdminSecurityContext adminSecurityContext = (AdminSecurityContext) ContextUtility.getInstance()
-				.getSecurityContextByUUID(DatabaseEnvironment.ADMIN_SECURITY_CONTEXT_UUID);
+				.getSecurityContextByUUID(AdminSecurityContext.ADMIN_SECURITY_CONTEXT_UUID);
 		return adminSecurityContext;
 	}
 	
diff --git a/src/main/java/org/gcube/informationsystem/resourceregistry/contexts/entities/ContextManagement.java b/src/main/java/org/gcube/informationsystem/resourceregistry/contexts/entities/ContextManagement.java
index 9db3857..7350d6d 100644
--- a/src/main/java/org/gcube/informationsystem/resourceregistry/contexts/entities/ContextManagement.java
+++ b/src/main/java/org/gcube/informationsystem/resourceregistry/contexts/entities/ContextManagement.java
@@ -30,8 +30,8 @@ import org.gcube.informationsystem.resourceregistry.api.exceptions.context.Conte
 import org.gcube.informationsystem.resourceregistry.api.exceptions.schema.SchemaViolationException;
 import org.gcube.informationsystem.resourceregistry.contexts.ContextUtility;
 import org.gcube.informationsystem.resourceregistry.contexts.relations.IsParentOfManagement;
+import org.gcube.informationsystem.resourceregistry.contexts.security.ContextSecurityContext;
 import org.gcube.informationsystem.resourceregistry.contexts.security.SecurityContext;
-import org.gcube.informationsystem.resourceregistry.dbinitialization.DatabaseEnvironment;
 import org.gcube.informationsystem.resourceregistry.instances.base.entities.EntityElementManagement;
 import org.gcube.informationsystem.resourceregistry.utils.Utility;
 import org.gcube.informationsystem.types.reference.entities.EntityType;
@@ -111,7 +111,7 @@ public class ContextManagement extends EntityElementManagement<Context, EntityTy
 	protected SecurityContext getWorkingContext() throws ResourceRegistryException {
 		if (workingContext == null) {
 			workingContext = ContextUtility.getInstance()
-					.getSecurityContextByUUID(DatabaseEnvironment.CONTEXT_SECURITY_CONTEXT_UUID);
+					.getSecurityContextByUUID(ContextSecurityContext.CONTEXT_SECURITY_CONTEXT_UUID);
 		}
 		return workingContext;
 	}
diff --git a/src/main/java/org/gcube/informationsystem/resourceregistry/contexts/relations/IsParentOfManagement.java b/src/main/java/org/gcube/informationsystem/resourceregistry/contexts/relations/IsParentOfManagement.java
index d188025..4bf359e 100644
--- a/src/main/java/org/gcube/informationsystem/resourceregistry/contexts/relations/IsParentOfManagement.java
+++ b/src/main/java/org/gcube/informationsystem/resourceregistry/contexts/relations/IsParentOfManagement.java
@@ -16,8 +16,8 @@ import org.gcube.informationsystem.resourceregistry.api.exceptions.relation.ispa
 import org.gcube.informationsystem.resourceregistry.api.exceptions.schema.SchemaViolationException;
 import org.gcube.informationsystem.resourceregistry.contexts.ContextUtility;
 import org.gcube.informationsystem.resourceregistry.contexts.entities.ContextManagement;
+import org.gcube.informationsystem.resourceregistry.contexts.security.ContextSecurityContext;
 import org.gcube.informationsystem.resourceregistry.contexts.security.SecurityContext;
-import org.gcube.informationsystem.resourceregistry.dbinitialization.DatabaseEnvironment;
 import org.gcube.informationsystem.resourceregistry.instances.base.relations.RelationElementManagement;
 import org.gcube.informationsystem.resourceregistry.utils.Utility;
 import org.gcube.informationsystem.types.reference.entities.EntityType;
@@ -52,7 +52,7 @@ public class IsParentOfManagement extends RelationElementManagement<ContextManag
 	protected SecurityContext getWorkingContext() throws ResourceRegistryException {
 		if (workingContext == null) {
 			workingContext = ContextUtility.getInstance()
-					.getSecurityContextByUUID(DatabaseEnvironment.CONTEXT_SECURITY_CONTEXT_UUID);
+					.getSecurityContextByUUID(ContextSecurityContext.CONTEXT_SECURITY_CONTEXT_UUID);
 		}
 		return workingContext;
 	}
diff --git a/src/main/java/org/gcube/informationsystem/resourceregistry/contexts/security/AdminSecurityContext.java b/src/main/java/org/gcube/informationsystem/resourceregistry/contexts/security/AdminSecurityContext.java
index 5a2b2d1..d7e5357 100644
--- a/src/main/java/org/gcube/informationsystem/resourceregistry/contexts/security/AdminSecurityContext.java
+++ b/src/main/java/org/gcube/informationsystem/resourceregistry/contexts/security/AdminSecurityContext.java
@@ -1,5 +1,7 @@
 package org.gcube.informationsystem.resourceregistry.contexts.security;
 
+import java.util.UUID;
+
 import org.gcube.informationsystem.resourceregistry.api.exceptions.ResourceRegistryException;
 import org.gcube.informationsystem.resourceregistry.dbinitialization.DatabaseEnvironment;
 import org.slf4j.Logger;
@@ -16,8 +18,16 @@ public class AdminSecurityContext extends SecurityContext {
 	
 	private static Logger logger = LoggerFactory.getLogger(SecurityContext.class);
 	
+	public static final String ADMIN_SECURITY_CONTEXT;
+	public static final UUID ADMIN_SECURITY_CONTEXT_UUID;
+	
+	static {
+		ADMIN_SECURITY_CONTEXT = "00000000-0000-0000-0000-000000000000";
+		ADMIN_SECURITY_CONTEXT_UUID = UUID.fromString(ADMIN_SECURITY_CONTEXT);
+	}
+	
 	public AdminSecurityContext() throws ResourceRegistryException {
-		super(DatabaseEnvironment.ADMIN_SECURITY_CONTEXT_UUID, false);
+		super(ADMIN_SECURITY_CONTEXT_UUID, false);
 	}
 	
 	@Override
diff --git a/src/main/java/org/gcube/informationsystem/resourceregistry/contexts/security/ContextSecurityContext.java b/src/main/java/org/gcube/informationsystem/resourceregistry/contexts/security/ContextSecurityContext.java
index 3f35681..fab84da 100644
--- a/src/main/java/org/gcube/informationsystem/resourceregistry/contexts/security/ContextSecurityContext.java
+++ b/src/main/java/org/gcube/informationsystem/resourceregistry/contexts/security/ContextSecurityContext.java
@@ -1,7 +1,8 @@
 package org.gcube.informationsystem.resourceregistry.contexts.security;
 
+import java.util.UUID;
+
 import org.gcube.informationsystem.resourceregistry.api.exceptions.ResourceRegistryException;
-import org.gcube.informationsystem.resourceregistry.dbinitialization.DatabaseEnvironment;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
@@ -15,8 +16,16 @@ public class ContextSecurityContext extends SecurityContext {
 	
 	private static Logger logger = LoggerFactory.getLogger(SecurityContext.class);
 	
+	public static final String CONTEXT_SECURITY_CONTEXT;
+	public static final UUID CONTEXT_SECURITY_CONTEXT_UUID;
+	
+	static {
+		CONTEXT_SECURITY_CONTEXT = "ffffffff-ffff-ffff-ffff-ffffffffffff";
+		CONTEXT_SECURITY_CONTEXT_UUID = UUID.fromString(CONTEXT_SECURITY_CONTEXT);
+	}
+	
 	public ContextSecurityContext() throws ResourceRegistryException {
-		super(DatabaseEnvironment.CONTEXT_SECURITY_CONTEXT_UUID, false);
+		super(CONTEXT_SECURITY_CONTEXT_UUID, false);
 	}
 	
 	@Override
diff --git a/src/main/java/org/gcube/informationsystem/resourceregistry/contexts/security/QueryTemplatesSecurityContext.java b/src/main/java/org/gcube/informationsystem/resourceregistry/contexts/security/QueryTemplatesSecurityContext.java
new file mode 100644
index 0000000..62f7455
--- /dev/null
+++ b/src/main/java/org/gcube/informationsystem/resourceregistry/contexts/security/QueryTemplatesSecurityContext.java
@@ -0,0 +1,53 @@
+package org.gcube.informationsystem.resourceregistry.contexts.security;
+
+import java.util.UUID;
+
+import org.gcube.informationsystem.resourceregistry.api.exceptions.ResourceRegistryException;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import com.orientechnologies.orient.core.metadata.security.ORole;
+import com.orientechnologies.orient.core.metadata.security.ORule;
+
+/**
+ * @author Luca Frosini (ISTI - CNR)
+ */
+public class QueryTemplatesSecurityContext extends SecurityContext {
+	
+	private static Logger logger = LoggerFactory.getLogger(SecurityContext.class);
+	
+	public static final String TEMPLATES_SECURITY_CONTEXT;
+	public static final UUID TEMPLATES_SECURITY_CONTEXT_UUID;
+	
+	static {
+		TEMPLATES_SECURITY_CONTEXT = "dddddddd-dddd-dddd-dddd-dddddddddddd";
+		TEMPLATES_SECURITY_CONTEXT_UUID = UUID.fromString(TEMPLATES_SECURITY_CONTEXT);
+	}
+	
+	public QueryTemplatesSecurityContext() throws ResourceRegistryException {
+		super(TEMPLATES_SECURITY_CONTEXT_UUID, false);
+	}
+	
+	@Override
+	protected ORole addExtraRules(ORole role, PermissionMode permissionMode) {
+		logger.trace("Adding extra rules for {}", role.getName());
+		switch(permissionMode) {
+			case WRITER:
+				role.addRule(ORule.ResourceGeneric.CLUSTER, null, ORole.PERMISSION_ALL);
+				role.addRule(ORule.ResourceGeneric.SYSTEM_CLUSTERS, null, ORole.PERMISSION_ALL);
+				role.addRule(ORule.ResourceGeneric.CLASS, null, ORole.PERMISSION_ALL);
+				break;
+			
+			case READER:
+				role.addRule(ORule.ResourceGeneric.CLUSTER, null, ORole.PERMISSION_READ);
+				role.addRule(ORule.ResourceGeneric.SYSTEM_CLUSTERS, null, ORole.PERMISSION_READ);
+				role.addRule(ORule.ResourceGeneric.CLASS, null, ORole.PERMISSION_READ);
+				break;
+			
+			default:
+				break;
+		}
+		return role;
+	}
+	
+}
diff --git a/src/main/java/org/gcube/informationsystem/resourceregistry/contexts/security/SchemaSecurityContext.java b/src/main/java/org/gcube/informationsystem/resourceregistry/contexts/security/SchemaSecurityContext.java
index 372c0ae..9560f92 100644
--- a/src/main/java/org/gcube/informationsystem/resourceregistry/contexts/security/SchemaSecurityContext.java
+++ b/src/main/java/org/gcube/informationsystem/resourceregistry/contexts/security/SchemaSecurityContext.java
@@ -1,7 +1,8 @@
 package org.gcube.informationsystem.resourceregistry.contexts.security;
 
+import java.util.UUID;
+
 import org.gcube.informationsystem.resourceregistry.api.exceptions.ResourceRegistryException;
-import org.gcube.informationsystem.resourceregistry.dbinitialization.DatabaseEnvironment;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
@@ -15,8 +16,17 @@ public class SchemaSecurityContext extends SecurityContext {
 	
 	private static Logger logger = LoggerFactory.getLogger(SecurityContext.class);
 	
+	// Used to persist Schemas
+	public static final String SCHEMA_SECURITY_CONTEXT;
+	public static final UUID SCHEMA_SECURITY_CONTEXT_UUID;
+
+	static {
+		SCHEMA_SECURITY_CONTEXT = "eeeeeeee-eeee-eeee-eeee-eeeeeeeeeeee";
+		SCHEMA_SECURITY_CONTEXT_UUID = UUID.fromString(SCHEMA_SECURITY_CONTEXT);
+	}
+	
 	public SchemaSecurityContext() throws ResourceRegistryException {
-		super(DatabaseEnvironment.SCHEMA_SECURITY_CONTEXT_UUID, false);
+		super(SCHEMA_SECURITY_CONTEXT_UUID, false);
 	}
 	
 	@Override
diff --git a/src/main/java/org/gcube/informationsystem/resourceregistry/contexts/security/SecurityContext.java b/src/main/java/org/gcube/informationsystem/resourceregistry/contexts/security/SecurityContext.java
index d409637..e01a397 100644
--- a/src/main/java/org/gcube/informationsystem/resourceregistry/contexts/security/SecurityContext.java
+++ b/src/main/java/org/gcube/informationsystem/resourceregistry/contexts/security/SecurityContext.java
@@ -20,6 +20,7 @@ import org.gcube.informationsystem.resourceregistry.api.exceptions.ResourceRegis
 import org.gcube.informationsystem.resourceregistry.contexts.ContextUtility;
 import org.gcube.informationsystem.resourceregistry.dbinitialization.DatabaseEnvironment;
 import org.gcube.informationsystem.resourceregistry.utils.Utility;
+import org.gcube.informationsystem.utils.UUIDManager;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
@@ -296,7 +297,7 @@ public class SecurityContext {
 				String[] list = name.split("_");
 				if (list.length == 2) {
 					String contextUUID = list[1];
-					if (!DatabaseEnvironment.RESERVED_CONTEX_UUID_STRING.contains(contextUUID)) {
+					if (!UUIDManager.isReservedUUID(contextUUID)) {
 						contexts.add(contextUUID);
 					}
 				}
diff --git a/src/main/java/org/gcube/informationsystem/resourceregistry/dbinitialization/DatabaseEnvironment.java b/src/main/java/org/gcube/informationsystem/resourceregistry/dbinitialization/DatabaseEnvironment.java
index 83585a4..2a18b4c 100644
--- a/src/main/java/org/gcube/informationsystem/resourceregistry/dbinitialization/DatabaseEnvironment.java
+++ b/src/main/java/org/gcube/informationsystem/resourceregistry/dbinitialization/DatabaseEnvironment.java
@@ -6,13 +6,10 @@ import java.net.URL;
 import java.security.Key;
 import java.util.ArrayList;
 import java.util.HashMap;
-import java.util.HashSet;
 import java.util.List;
 import java.util.Map;
 import java.util.Properties;
 import java.util.ServiceLoader;
-import java.util.Set;
-import java.util.UUID;
 
 import org.gcube.common.encryption.SymmetricKey;
 import org.gcube.informationsystem.base.reference.AccessType;
@@ -25,6 +22,7 @@ import org.gcube.informationsystem.model.reference.properties.Property;
 import org.gcube.informationsystem.resourceregistry.contexts.ContextUtility;
 import org.gcube.informationsystem.resourceregistry.contexts.security.AdminSecurityContext;
 import org.gcube.informationsystem.resourceregistry.contexts.security.ContextSecurityContext;
+import org.gcube.informationsystem.resourceregistry.contexts.security.QueryTemplatesSecurityContext;
 import org.gcube.informationsystem.resourceregistry.contexts.security.SchemaSecurityContext;
 import org.gcube.informationsystem.resourceregistry.contexts.security.SecurityContext.PermissionMode;
 import org.gcube.informationsystem.resourceregistry.instances.base.ElementManagement;
@@ -115,21 +113,7 @@ public class DatabaseEnvironment {
 	public static final String DB_URI;
 	
 	public static final CONNECTION_STRATEGY CONNECTION_STRATEGY_PARAMETER = CONNECTION_STRATEGY.ROUND_ROBIN_CONNECT;
-	
-	// Used to indicate virtual admin security context
-	private static final String ADMIN_SECURITY_CONTEXT;
-	public static final UUID ADMIN_SECURITY_CONTEXT_UUID;
-	
-	// Used to persist Schemas
-	private static final String SCHEMA_SECURITY_CONTEXT;
-	public static final UUID SCHEMA_SECURITY_CONTEXT_UUID;
-	
-	// Used to Persist Context and their relations
-	private static final String CONTEXT_SECURITY_CONTEXT;
-	public static final UUID CONTEXT_SECURITY_CONTEXT_UUID;
-	
-	public static final Set<String> RESERVED_CONTEX_UUID_STRING;
-	public static final Set<UUID> RESERVED_CONTEX_UUID;
+
 	
 	protected static final String DB_KEY_FILENAME_VARNAME = "DB_KEY_FILENAME";
 	protected static final String DB_KEY_ALGORITHM_VARNAME = "DB_KEY_ALGORITHM";
@@ -194,26 +178,7 @@ public class DatabaseEnvironment {
 			throw new RuntimeException("Unable to load properties", e);
 		}
 		
-		RESERVED_CONTEX_UUID_STRING = new HashSet<>();
-		RESERVED_CONTEX_UUID = new HashSet<>();
-		
-		
-		ADMIN_SECURITY_CONTEXT = "00000000-0000-0000-0000-000000000000";
-		RESERVED_CONTEX_UUID_STRING.add(ADMIN_SECURITY_CONTEXT);
-		ADMIN_SECURITY_CONTEXT_UUID = UUID.fromString(ADMIN_SECURITY_CONTEXT);
-		RESERVED_CONTEX_UUID.add(ADMIN_SECURITY_CONTEXT_UUID);
-		
-		// Used to persist Schemas
-		SCHEMA_SECURITY_CONTEXT = "eeeeeeee-eeee-eeee-eeee-eeeeeeeeeeee";
-		RESERVED_CONTEX_UUID_STRING.add(SCHEMA_SECURITY_CONTEXT);
-		SCHEMA_SECURITY_CONTEXT_UUID = UUID.fromString(SCHEMA_SECURITY_CONTEXT);
-		RESERVED_CONTEX_UUID.add(SCHEMA_SECURITY_CONTEXT_UUID);
-		
 		// Used to Persist Context and their relations
-		CONTEXT_SECURITY_CONTEXT = "ffffffff-ffff-ffff-ffff-ffffffffffff";
-		RESERVED_CONTEX_UUID_STRING.add(CONTEXT_SECURITY_CONTEXT);
-		CONTEXT_SECURITY_CONTEXT_UUID = UUID.fromString(CONTEXT_SECURITY_CONTEXT);
-		RESERVED_CONTEX_UUID.add(CONTEXT_SECURITY_CONTEXT_UUID);
 		
 		try {
 			boolean created = initGraphDB();
@@ -223,6 +188,9 @@ public class DatabaseEnvironment {
 			AdminSecurityContext adminSecurityContext = new AdminSecurityContext();
 			contextUtility.addSecurityContext(adminSecurityContext.getUUID().toString(), adminSecurityContext);
 			
+			QueryTemplatesSecurityContext queryTemplatesSecurityContext = new QueryTemplatesSecurityContext();
+			contextUtility.addSecurityContext(queryTemplatesSecurityContext.getUUID().toString(), queryTemplatesSecurityContext);
+			
 			ContextSecurityContext contextSecurityContext = new ContextSecurityContext();
 			contextUtility.addSecurityContext(contextSecurityContext.getUUID().toString(), contextSecurityContext);
 			
diff --git a/src/main/java/org/gcube/informationsystem/resourceregistry/types/entities/EntityTypeDefinitionManagement.java b/src/main/java/org/gcube/informationsystem/resourceregistry/types/entities/EntityTypeDefinitionManagement.java
index a2dc771..242e41c 100644
--- a/src/main/java/org/gcube/informationsystem/resourceregistry/types/entities/EntityTypeDefinitionManagement.java
+++ b/src/main/java/org/gcube/informationsystem/resourceregistry/types/entities/EntityTypeDefinitionManagement.java
@@ -14,8 +14,8 @@ import org.gcube.informationsystem.resourceregistry.api.exceptions.schema.Schema
 import org.gcube.informationsystem.resourceregistry.api.exceptions.schema.SchemaNotFoundException;
 import org.gcube.informationsystem.resourceregistry.api.exceptions.schema.SchemaViolationException;
 import org.gcube.informationsystem.resourceregistry.contexts.ContextUtility;
+import org.gcube.informationsystem.resourceregistry.contexts.security.SchemaSecurityContext;
 import org.gcube.informationsystem.resourceregistry.contexts.security.SecurityContext;
-import org.gcube.informationsystem.resourceregistry.dbinitialization.DatabaseEnvironment;
 import org.gcube.informationsystem.resourceregistry.instances.base.ElementManagementUtility;
 import org.gcube.informationsystem.resourceregistry.instances.base.entities.EntityElementManagement;
 import org.gcube.informationsystem.resourceregistry.utils.Utility;
@@ -51,7 +51,7 @@ public abstract class EntityTypeDefinitionManagement<E extends EntityType> exten
 	protected SecurityContext getWorkingContext() throws ResourceRegistryException {
 		if (workingContext == null) {
 			workingContext = ContextUtility.getInstance()
-					.getSecurityContextByUUID(DatabaseEnvironment.SCHEMA_SECURITY_CONTEXT_UUID);
+					.getSecurityContextByUUID(SchemaSecurityContext.SCHEMA_SECURITY_CONTEXT_UUID);
 		}
 		return workingContext;
 	}
diff --git a/src/main/java/org/gcube/informationsystem/resourceregistry/types/properties/PropertyTypeDefinitionManagement.java b/src/main/java/org/gcube/informationsystem/resourceregistry/types/properties/PropertyTypeDefinitionManagement.java
index 9babfab..019b16f 100644
--- a/src/main/java/org/gcube/informationsystem/resourceregistry/types/properties/PropertyTypeDefinitionManagement.java
+++ b/src/main/java/org/gcube/informationsystem/resourceregistry/types/properties/PropertyTypeDefinitionManagement.java
@@ -13,8 +13,8 @@ import org.gcube.informationsystem.resourceregistry.api.exceptions.schema.Schema
 import org.gcube.informationsystem.resourceregistry.api.exceptions.schema.SchemaNotFoundException;
 import org.gcube.informationsystem.resourceregistry.api.exceptions.schema.SchemaViolationException;
 import org.gcube.informationsystem.resourceregistry.contexts.ContextUtility;
+import org.gcube.informationsystem.resourceregistry.contexts.security.SchemaSecurityContext;
 import org.gcube.informationsystem.resourceregistry.contexts.security.SecurityContext;
-import org.gcube.informationsystem.resourceregistry.dbinitialization.DatabaseEnvironment;
 import org.gcube.informationsystem.resourceregistry.instances.base.ElementManagement;
 import org.gcube.informationsystem.resourceregistry.instances.base.ElementManagementUtility;
 import org.gcube.informationsystem.resourceregistry.utils.Utility;
@@ -58,7 +58,7 @@ public class PropertyTypeDefinitionManagement extends ElementManagement<OElement
 	protected SecurityContext getWorkingContext() throws ResourceRegistryException {
 		if(workingContext == null) {
 			workingContext = ContextUtility.getInstance()
-					.getSecurityContextByUUID(DatabaseEnvironment.SCHEMA_SECURITY_CONTEXT_UUID);
+					.getSecurityContextByUUID(SchemaSecurityContext.SCHEMA_SECURITY_CONTEXT_UUID);
 		}
 		return workingContext;
 	}
diff --git a/src/main/java/org/gcube/informationsystem/resourceregistry/types/relations/RelationTypeDefinitionManagement.java b/src/main/java/org/gcube/informationsystem/resourceregistry/types/relations/RelationTypeDefinitionManagement.java
index c6017cd..57a75c4 100644
--- a/src/main/java/org/gcube/informationsystem/resourceregistry/types/relations/RelationTypeDefinitionManagement.java
+++ b/src/main/java/org/gcube/informationsystem/resourceregistry/types/relations/RelationTypeDefinitionManagement.java
@@ -16,8 +16,8 @@ import org.gcube.informationsystem.resourceregistry.api.exceptions.schema.Schema
 import org.gcube.informationsystem.resourceregistry.api.exceptions.schema.SchemaNotFoundException;
 import org.gcube.informationsystem.resourceregistry.api.exceptions.schema.SchemaViolationException;
 import org.gcube.informationsystem.resourceregistry.contexts.ContextUtility;
+import org.gcube.informationsystem.resourceregistry.contexts.security.SchemaSecurityContext;
 import org.gcube.informationsystem.resourceregistry.contexts.security.SecurityContext;
-import org.gcube.informationsystem.resourceregistry.dbinitialization.DatabaseEnvironment;
 import org.gcube.informationsystem.resourceregistry.instances.base.ElementManagementUtility;
 import org.gcube.informationsystem.resourceregistry.instances.base.relations.RelationElementManagement;
 import org.gcube.informationsystem.resourceregistry.types.entities.EntityTypeDefinitionManagement;
@@ -62,7 +62,7 @@ public abstract class RelationTypeDefinitionManagement<T extends EntityTypeDefin
 	protected SecurityContext getWorkingContext() throws ResourceRegistryException {
 		if (workingContext == null) {
 			this.workingContext = ContextUtility.getInstance()
-					.getSecurityContextByUUID(DatabaseEnvironment.SCHEMA_SECURITY_CONTEXT_UUID);
+					.getSecurityContextByUUID(SchemaSecurityContext.SCHEMA_SECURITY_CONTEXT_UUID);
 		}
 		return workingContext;
 	}
diff --git a/src/main/java/org/gcube/informationsystem/resourceregistry/utils/HeaderUtility.java b/src/main/java/org/gcube/informationsystem/resourceregistry/utils/HeaderUtility.java
index 05ba129..e57a052 100644
--- a/src/main/java/org/gcube/informationsystem/resourceregistry/utils/HeaderUtility.java
+++ b/src/main/java/org/gcube/informationsystem/resourceregistry/utils/HeaderUtility.java
@@ -16,6 +16,7 @@ import org.gcube.informationsystem.base.reference.IdentifiableElement;
 import org.gcube.informationsystem.model.reference.properties.Header;
 import org.gcube.informationsystem.resourceregistry.api.exceptions.ResourceRegistryException;
 import org.gcube.informationsystem.utils.ElementMapper;
+import org.gcube.informationsystem.utils.UUIDManager;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
@@ -52,7 +53,7 @@ public class HeaderUtility {
 		HeaderOrient header = new HeaderOrient();
 		
 		if(uuid == null) {
-			uuid = UUID.randomUUID();
+			uuid = UUIDManager.generateValidRandomUUID();
 		}
 		
 		header.setUUID(uuid);
@@ -72,7 +73,7 @@ public class HeaderUtility {
 	}
 	
 	public static Header getHeader(JsonNode jsonNode, boolean creation)
-			throws JsonParseException, JsonMappingException, IOException {
+			throws JsonParseException, JsonMappingException, IOException, ResourceRegistryException {
 		if(jsonNode.has(IdentifiableElement.HEADER_PROPERTY)) {
 			JsonNode headerNode = jsonNode.get(IdentifiableElement.HEADER_PROPERTY);
 			if(headerNode.isNull()) {
@@ -80,9 +81,12 @@ public class HeaderUtility {
 			}
 			HeaderOrient header = null;
 			if(creation) {
-				// If an header is provided MUST contains and UUID otherwise is
+				// If an header is provided, it MUST contains an UUID otherwise is
 				// an invalid request so that let that an exception is raised
 				UUID uuid = UUID.fromString(headerNode.get(Header.UUID_PROPERTY).asText());
+				if(UUIDManager.isReservedUUID(uuid)) {
+					throw new ResourceRegistryException("The provided UUID " + uuid.toString() + "is reserved. The reserved UUID are : " + UUIDManager.getAllReservedUUIDAsStrings());
+				}
 				header = (HeaderOrient) createHeader(uuid);
 			} else {
 				header = new HeaderOrient();