code: public int deleteValue(String property, String value) {
  		int count = 0;
  		if (has()) {
  			Map<String, Object> fieldValues = buildFieldValues(property, value);
  			count = getDao().delete(fieldValues);
  		}
  		return count;
  	}
docs: Delete the property value
  
  @param property
  property name
  @param value
  property value
  @return deleted values count