Linq to Entities - 使用“自引用”检索实体来自存储过程
我不太明白这一点。我有一个名为 Employee 的表，其中包含 Id 字段。该表还包含一个 ManagerId 字段，该字段具有指向 Employee's Id 字段的外键。当我将表作为实体添加到实体数据模型时，它会创建带有 EmployeeChildren 集合元素和 EmployeeParent 元素的新 Employee 实体。我可以检索所有员工并将它们完美地放入 Employee 实体的新实例中。员工实体将有许多子实体，每个子实体可以有许多自己的子实体，并且每个子实体都有一个指向其父实体的指针。
我现在需要做的是使用存储过程检索这些员工的子集。现在，如果我搜索员工 John Doe，他的上方有 2 个人，存储过程将返回 3 行。
EmployeeID ManagerId Name
1 null Bill
2 1 Jane
3 2 John Doe
这是我执行检索的代码：
using (var entity = new TimeEntryEntities())
{
var employees =
from E in entity.EmployeeSearch(search)
orderby E.Name
select E;
return employees.ToList<Employee>();
}
现在，此代码返回 3 个单独的实体。我怎样才能将它们组合在一起？
I can't quite figure this out. I have a table called Employee with and Id field. The table also contains a ManagerId field which has a foreign key pointing to the Employee's Id field. When I add the table as an entity to my entity data model it creates the new Employee entity with an EmployeeChildren collection element and an EmployeeParent element. I can retrieve all employee's and have them put into a new instance of the Employee entity perfect. The employee entity will have many children, each child entity can have many children of their own and each one has a pointer back to it's parent.
What I need to do now is retrieve a subset of those employee's using a stored procedure. Right now, if I search for employee John Doe, who has 2 people above him, the stored procedure will return 3 rows.
EmployeeID ManagerId Name
1 null Bill
2 1 Jane
3 2 John Doe
Here is my code to do the retrieval:
using (var entity = new TimeEntryEntities())
{
var employees =
from E in entity.EmployeeSearch(search)
orderby E.Name
select E;
return employees.ToList<Employee>();
}
Right now, this code returns 3 separate entities. How can I have it group them together into one?
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听起来您正试图展平层次结构，因此只返回一条记录。也许存储过程中的通用表表达式 (CTE) 可以提供帮助：
这是一个替代方案类似的请求：
还有另一个更详细的示例（但您必须免费注册）：
It sound like you are trying to flatten out the hierarchy so only one record is returned. Maybe Common Table Expression (CTE) in the stored procedure can help:
Here is an alternate of a similar request:
Also another example with more detail (but you have to register for free):
您应该仅返回您感兴趣的实体。EF 将自动为您检索相关实体。
如果您不使用自我引用，这会更容易可视化，这个概念已经成为障碍。
You should return only the entity you're interested in. EF will retrieve the related entities automatically for you.
This would be easier to visualize if you we're not using a self-reference, this concept has got in the way.