Gets and sets the Exists property.
Check for the existence of the attribute used for the conditional check.
If this field is unspecified or true, UpdateCondition.Value must be set to a value.
If this field is false, UpdateCondition.Value should not have a value assigned to it.
If no value is associated with this field, SimpleDB uses a default value of 'true'

C# |
public bool Exists { get; set; }