diff --git a/src/main/java/org/gcube/accounting/datamodel/implementations/StorageUsageRecord.java b/src/main/java/org/gcube/accounting/datamodel/implementations/StorageUsageRecord.java
index 9b1e508..3b5c8ef 100644
--- a/src/main/java/org/gcube/accounting/datamodel/implementations/StorageUsageRecord.java
+++ b/src/main/java/org/gcube/accounting/datamodel/implementations/StorageUsageRecord.java
@@ -14,6 +14,7 @@ import org.gcube.accounting.datamodel.validations.annotations.NotEmptyIfNotNull;
 import org.gcube.accounting.datamodel.validations.annotations.ValidIP;
 import org.gcube.accounting.datamodel.validations.annotations.ValidInteger;
 import org.gcube.accounting.datamodel.validations.annotations.ValidLong;
+import org.gcube.accounting.datamodel.validations.annotations.ValidOperationType;
 import org.gcube.accounting.exception.InvalidValueException;
 
 /**
@@ -27,11 +28,19 @@ public class StorageUsageRecord extends RawUsageRecord implements SingleUsageRec
 	 */
 	private static final long serialVersionUID = 1381025822586583326L;
 
+	/*
+	 * Actually workspace uses
+	 * DOWNLOAD, UPLOAD, COPY, MOVE, DELETE,
+	 */
+	public enum OperationType {
+		GET, PUT, UPDATE, DELETE
+	}
+	
 	@NotEmptyIfNotNull
 	public static final String PROVIDER_ID = "providerId";
 	@NotEmptyIfNotNull
 	public static final String OBJECT_URI = "objectURI";
-	@RequiredField @NotEmpty
+	@RequiredField @ValidOperationType
 	public static final String OPERATION_TYPE = "operationType";
 	@NotEmpty
 	public static final String QUALIFIER = "qualifier";
diff --git a/src/main/java/org/gcube/accounting/datamodel/implementations/TaskUsageRecord.java b/src/main/java/org/gcube/accounting/datamodel/implementations/TaskUsageRecord.java
index 1394803..cd5dbab 100644
--- a/src/main/java/org/gcube/accounting/datamodel/implementations/TaskUsageRecord.java
+++ b/src/main/java/org/gcube/accounting/datamodel/implementations/TaskUsageRecord.java
@@ -11,10 +11,10 @@ import org.gcube.accounting.datamodel.RawUsageRecord;
 import org.gcube.accounting.datamodel.SingleUsageRecord;
 import org.gcube.accounting.datamodel.decorators.RequiredField;
 import org.gcube.accounting.datamodel.deprecationmanagement.annotations.DeprecatedWarning;
+import org.gcube.accounting.datamodel.deprecationmanagement.annotations.MoveToOperationResult;
 import org.gcube.accounting.datamodel.validations.annotations.NotEmpty;
 import org.gcube.accounting.datamodel.validations.annotations.ValidInteger;
 import org.gcube.accounting.datamodel.validations.annotations.ValidLong;
-import org.gcube.accounting.datamodel.validations.annotations.ValidOperationResult;
 import org.gcube.accounting.exception.InvalidValueException;
 
 /**
@@ -46,8 +46,10 @@ public class TaskUsageRecord extends RawUsageRecord implements SingleUsageRecord
 	public static final String USAGE_START_TIME = "usageStartTime";
 	@RequiredField @ValidLong
 	public static final String USAGE_END_TIME = "usageEndTime";
-	@ValidOperationResult
-	public static final String USAGE_PHASE = "usagePhase";
+	
+	@MoveToOperationResult
+	protected static final String USAGE_PHASE = "usagePhase";
+	
 	@ValidInteger
 	public static final String INPUT_FILES_NUMBER = "inputFilesNumber";
 	@ValidLong
@@ -134,6 +136,7 @@ public class TaskUsageRecord extends RawUsageRecord implements SingleUsageRecord
 		
 	}
 	
+	/*
 	public USAGE_PHASE getUsagePhase() {
 		return (USAGE_PHASE) this.resourceProperties.get(USAGE_PHASE);
 	}
@@ -141,6 +144,7 @@ public class TaskUsageRecord extends RawUsageRecord implements SingleUsageRecord
 	public void setUsagePhase(USAGE_PHASE usagePhase) throws InvalidValueException {
 		setResourceProperty(USAGE_PHASE, usagePhase);
 	}
+	*/
 
 	public int getInputFilesNumber() {
 		return (Integer) this.resourceProperties.get(INPUT_FILES_NUMBER);
diff --git a/src/main/java/org/gcube/accounting/datamodel/validations/annotations/ValidOperationType.java b/src/main/java/org/gcube/accounting/datamodel/validations/annotations/ValidOperationType.java
new file mode 100644
index 0000000..098c1b0
--- /dev/null
+++ b/src/main/java/org/gcube/accounting/datamodel/validations/annotations/ValidOperationType.java
@@ -0,0 +1,16 @@
+package org.gcube.accounting.datamodel.validations.annotations;
+
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+
+import org.gcube.accounting.datamodel.decorators.FieldDecorator;
+import org.gcube.accounting.datamodel.validations.validators.ValidOperationTypeValidator;
+
+@Target(ElementType.FIELD)
+@Retention(RetentionPolicy.RUNTIME)
+@FieldDecorator(managed=ValidOperationTypeValidator.class) 
+public @interface ValidOperationType {
+
+}
diff --git a/src/main/java/org/gcube/accounting/datamodel/validations/validators/ValidOperationTypeValidator.java b/src/main/java/org/gcube/accounting/datamodel/validations/validators/ValidOperationTypeValidator.java
new file mode 100644
index 0000000..a0ff8f8
--- /dev/null
+++ b/src/main/java/org/gcube/accounting/datamodel/validations/validators/ValidOperationTypeValidator.java
@@ -0,0 +1,62 @@
+package org.gcube.accounting.datamodel.validations.validators;
+
+import java.io.Serializable;
+
+import org.gcube.accounting.datamodel.UsageRecord;
+import org.gcube.accounting.datamodel.UsageRecord.OperationResult;
+import org.gcube.accounting.datamodel.decorators.FieldAction;
+import org.gcube.accounting.datamodel.implementations.StorageUsageRecord.OperationType;
+import org.gcube.accounting.exception.InvalidValueException;
+
+public class ValidOperationTypeValidator implements FieldAction {
+
+	private static final String ERROR = String.format("Not Instance of %s", OperationResult.class.getSimpleName());
+	
+	/**
+	 * {@inheritDoc}
+	 */
+	@SuppressWarnings("rawtypes")
+	@Override
+	public Serializable validate(String key, Serializable value, UsageRecord usageRecord) throws InvalidValueException {
+		if(value instanceof OperationType){
+			return value;
+		}
+		
+		try {
+			if(value instanceof String){
+				try{
+					OperationType operationType = OperationType.valueOf((String) value);
+					if(operationType !=null){
+						return operationType;
+					}
+				} catch(Exception e){
+					// Trying another way
+				}
+				
+				try{
+					Integer integer = Integer.getInteger((String) value);
+					if(integer!=null){
+						value = integer;
+					}
+				} catch(Exception e){
+					// Trying another way
+				}
+			}
+			
+			if(value instanceof Integer){
+				return OperationType.values()[(Integer) value];
+			}
+			
+			if(value instanceof Enum){
+				return OperationType.values()[((Enum) value).ordinal()];
+			}
+			
+		}catch(Exception e){
+			throw new InvalidValueException(ERROR, e.getCause());
+		}
+		
+		throw new InvalidValueException(ERROR);
+	}
+	
+
+}