// - public abstract T Visit(DbSubtractExpression exp);
// - public override DbExpression Visit(DbSubtractExpression exp) { return(new DbSubtractExpression(exp.Type, this.MakeNewExpression(exp.Left), this.MakeNewExpression(exp.Right), exp.Method)); }
// - public virtual T Visit(DbSubtractExpression exp) { throw new NotImplementedException(); }