使用導航對象查詢實體框架

Question

我在下面有實體類，我想要一個像sql這樣的查詢，這對於實體框架來說怎麼樣？

select * from SiteUsers su 
inner join SiteUserRoles sur on su.Id=sur.SiteUserId 
inner join SiteRoleActions sra on sur.SiteRoleId = sra.SiteRoleId 
inner join SiteActions sa on sa.Id = sra.SiteActionId 
where su.Id=1 and sa.ParentId=189 



    public class SiteRole 
    { 
     public SiteRole() 
     { 
      this.SiteActions = new HashSet<SiteAction>(); 
      this.SiteUser = new HashSet<SiteUser>(); 
     } 

     public int Id { get; set; } 
     public string Name { get; set; } 
     public string Description { get; set; } 

     public virtual ICollection<SiteAction> SiteActions { get; set; } 
     public virtual ICollection<SiteUser> SiteUser { get; set; } 
    } 

public partial class SiteUser 
    { 
     public SiteUser() 
     { 
      this.SiteRoles = new HashSet<SiteRole>(); 
     } 

     public int Id { get; set; } 
     public string Email { get; set; } 
     public string UserPassword { get; set; } 
     public string UserName { get; set; } 
     public string LastName { get; set; } 
     public string FirstName { get; set; } 
     public Nullable<System.DateTime> DateCreated { get; set; } 

     public virtual ICollection<SiteRole> SiteRoles { get; set; } 
    } 

public partial class SiteAction 
    { 
     public SiteAction() 
     { 

      this.Childs = new HashSet<SiteAction>(); 
      this.SiteRoles = new HashSet<SiteRole>(); 
     } 

     public int Id { get; set; } 
     public string Name { get; set; } 
     public string ImagePath { get; set; } 
     public string ActionName { get; set; } 
     public string ControllerName { get; set; } 
     public Nullable<int> ParentId { get; set; } 
     public Nullable<int> Type { get; set; } 


     public virtual ICollection<SiteAction> Childs { get; set; } 
     public virtual SiteAction Parent { get; set; } 
     public virtual ICollection<SiteRole> SiteRoles { get; set; } 
    } 

    protected override void OnModelCreating(DbModelBuilder modelBuilder) 
    { 
     modelBuilder.Entity<SiteUser>().HasMany<SiteRole>(r => r.SiteRoles).WithMany(u => u.SiteUser).Map(m => 
     { 
      m.ToTable("SiteUserRoles"); 
      m.MapLeftKey("SiteUserId"); 
      m.MapRightKey("SiteRoleId"); 
     }); 

     modelBuilder.Entity<SiteRole>().HasMany<SiteAction>(r => r.SiteActions).WithMany(u => u.SiteRoles).Map(m => 
     { 
      m.ToTable("SiteRoleActions"); 
      m.MapLeftKey("SiteRoleId"); 
      m.MapRightKey("SiteActionId"); 
     }); 



     modelBuilder.Conventions.Remove<IncludeMetadataConvention>(); 
    } 

Answer 1

由於您沒有SiteUserRoles和SiteRoleActions作爲實體，但只作爲連接表（如果我讀了很好的話），您應該使用導航屬性代替連接。類似於：

conext.SiteUsers.Where(su => su.id == 1 
    && su.SiteRoles.SelectMany(sr => sr.SiteActions) 
     .Any(sa => sa.ParentId == 189) 

（未檢查語法）。

Answer 2

var result= (from su in SiteUsers 
      join sur in SiteUserRoles 
      on su.Id=sur.SiteUserId 
      join sra in SiteRoleActions 
      on sur.SiteRoleId = sra.SiteRoleId 
      join sa in SiteActions 
      on sra.SiteActionId=sa.Id 
      where su.Id=1 and sa.ParentId=189 
      select su).ToList(); 

希望這會有所幫助。結果將是一個SiteUsers類型的列表。