如何從多個表訪問數據

Question

如何編寫linq查詢以訪問多個表中的數據。如何為以下sql查詢編寫Linq查詢：-

"select * from user,employee where user.Name='smith' and employee.company='xyz'"

Answer 1

這樣的事情會做到的。

var q = from u in db.user
        from e in db.employee
        where u.Name == "smith" && e.company == "xyz"
        select new
        {
           User = u,
           Employee = e
        };

Answer 2

這取決於您使用的linq提供程序。 例如，假設您正確定義了外鍵，則實體框架將創建它們所謂的“導航屬性”。 因此，您可以通過這種方式輕松地編寫類似於上面的linq查詢：

var query = data.Where(employee => employee.Name == "Smith" && employee.Company.Name == "xyz");

Answer 3

var result = from u in context.User
             from e in context.Employee
             where (u.Name == "smith" && e.company == "xyz")