linq to sql navigation properties simple example

Question

For this kind of schema:

mainTable(Id,Name) //Id is primary key

secondryTable(mainTableId,RegDate,Age) // mainTableId is foreign key

Can anyone give me a example of Linq to Sql using navigation properites.

With join I am selecting as:

from mainT in db.mainTable
join secT in db.secondryTable on mainT.Id equals secT.mainTableId
select new { mainT.Name, secT.RegDate, secTable.Age}

Answer 1

我自己找到了一个解决方案:)查询将是：

FROM mainT in db.mainTable
SELECT new
    {
      mainT.Name,
      regDate = mainT.secT.Where(//some condition),
      age = mainT.secT.Where(//some condition)
    }

只有在数据库中正确定义了主键/外键关系时，上述查询才有效。