public override string ToAql()
        {
            string aql = "REPLACE " + KeyExpression.ToAql();

            if (WithExpression != null)
            {
                aql += " WITH " + WithExpression.ToAql();
            }

            aql += " IN " + CollectionName;

            if (Options.Count > 0)
            {
                aql += " OPTIONS " + Options.ToString();
            }

            return(aql);
        }