Linq 初学问题 求解释

[my_1234]

var q =
    from c in db.Customers
    from o in c.Orders
    where c.City == "London"
    select o;

db 为：**.dbml实例 两个表 Customers 和 Orders
问题：为什么我用c.Orders 不行，这两个表是怎么关联的？

[my_1234]

自己顶一个~~

[宝_爸]

两个表要用Join。如

  EmployeeInfoDataContext dbEmp = new EmployeeInfoDataContext();
        var query = from emp in dbEmp.Employees
                    join dept in dbEmp.Departments
                        on emp.DeptID equals dept.DeptID
                    select new 
                    {
                        EmpID = emp.EmpID,
                        EmpName = emp.EmpName,
                        Age = emp.Age,
                        Address = emp.Address,
                        DeptName = dept.DepartmentName
                    };

[my_1234]

3Q 吃饭去了，回来结贴