EF5代碼第一次遷移在嵌套層次結構內導航

Question

數據庫使用代碼優先遷移進行基因處理。

我有這樣的父子關係，每個人都有孩子，兒童可以有自己的孩子等

public class Person 
{ 
    public string Name { get; set; } 
    public bool Flagged { get; set; } 
    public virtual ICollection<Person> Children { get; set; } 
    public virtual Person Master { get; set; } 
    ... 
} 

什麼是找到這些東西的最有效的方法是什麼？到目前爲止，我一直在使用遞歸查詢，它似乎很慢，並不是一件好事。我讀了Common Table Expressions，但我不確定這是否適合我的需求並支持EF 代碼優先遷移。

1. 人員發現第一個標記爲「真」的主人。
2. 人發現所有嵌套的孩子。
3. 人員發現所有標記= true的嵌套子女。

Answer 1

AFAIK實體框架不支持公用表表達式。您應該繼續使用數據庫視圖。對於我來說，讓父母和孩子看起來像這樣。

WITH Children AS 
(
    SELECT a.* 
    FROM dbo.Persons a 
    WHERE Id = 14 
    UNION ALL 
    SELECT a.* 
    FROM dbo.Persons a JOIN Children c ON a.IdParentPerson = c.id 
) 
    SELECT * 
    FROM Children 
    /*WHERE Children.Flagged = true*/ /*IF REQUIRED*/ 

和

WITH Parents AS 
(
    SELECT a.* 
    FROM dbo.Persons a 
    WHERE Id = 16 
    UNION ALL 
    SELECT a.* 
    FROM dbo.Persons a JOIN Parents c ON a.Id = c.IdParentPerson 
) 
    SELECT * 
    FROM Parents 
    WHERE Parents.Flagged = true 

，然後用它在DbSet像

var id = YOUR_ID; 
using(var context = new Context()) 
{ 
    var query = context.Set<GroupEntity>().SqlQuery(
    " WITH Parents AS " + 
    " (" + 
    " SELECT a.* " + 
    " FROM dbo.Persons a " + 
    " WHERE Id = @Id " + 
    " UNION ALL " + 
    " SELECT a.* " + 
    " FROM dbo.Persons a JOIN Parents c ON a.Id = c.IdParentPerson " + 
    ") " + 
    " SELECT * " + 
    " FROM Parents " + 
    " WHERE Parents.Flagged = true " 
    , new SqlParameter("@Id", id)); 
}