功能NHibernate - 从底部

Question

例如查询层次结构的数据，如果我有这样的

id | parent_id 
----------------- 
1 | null 
2 | 1 
3 | 1 
4 | 1 
5 | 2 
6 | 3 
7 | 3 
8 | 4 
9 | 7 
.... 

表层次树看起来就像这样：

      X1 
          | 
------------------------------------------------------ 
|       |       | 
X2      X3       X4 
|       |       | 
|    ------------------     | 
|    |    |     | 
X5    X6    X7     X8 
            | 
            X9 

那么，有没有反正，我可以使用QueryOver或Criteria查询，当我输入id时，它会将所有parent_id（或父对象）的列表从其父项返回到顶部？例如：

input | result 
----------------------- 
1  | null 
2  | [1] 
3  | [1] 
5  | [2, 1] 
8  | [4, 1] 
9  | [7, 3, 1] 
.... 

==================

工作查询（但必须调用数据库两次）

var roleIds = session.CreateSQLQuery("SELECT Id FROM dbo.fn_get_parent_roles(:id)") 
       .SetInt32("id", roleId) 
       .List<int>(); 

Role x = null; 
var query = session.QueryOver<Role>(() => x) 
    .Where(Restrictions.In("x.RoleId", roleIds.ToArray())); 

= =================

更新时间：

var hierarchyQuery = new SQLCriterion(
       new SqlString("{alias}.RoleId IN (SELECT Id FROM dbo.fn_get_parent_roles(:id))"), 
       new object[] { roleId }, 
       new IType[] { NHibernateUtil.Int32 }); 
var results = session.QueryOver<Role>() 
      .Where(hierarchyQuery) 
      .List(); 

然后我得到这个消息：

Index was out of range. Must be non-negative and less than the size of the collection. 
Parameter name: index 

这里充满堆栈跟踪

at System.ThrowHelper.ThrowArgumentOutOfRangeException() 
    at System.Collections.Generic.List`1.get_Item(Int32 index) 
    at NHibernate.Criterion.SQLCriterion.ToSqlString(ICriteria criteria, ICriteriaQuery criteriaQuery, IDictionary`2 enabledFilters) 
    at NHibernate.Loader.Criteria.CriteriaQueryTranslator.GetWhereCondition(IDictionary`2 enabledFilters) 
    at NHibernate.Loader.Criteria.CriteriaJoinWalker..ctor(IOuterJoinLoadable persister, CriteriaQueryTranslator translator, ISessionFactoryImplementor factory, ICriteria criteria, String rootEntityName, IDictionary`2 enabledFilters) 
    at NHibernate.Loader.Criteria.CriteriaLoader..ctor(IOuterJoinLoadable persister, ISessionFactoryImplementor factory, CriteriaImpl rootCriteria, String rootEntityName, IDictionary`2 enabledFilters) 
    at NHibernate.Impl.SessionImpl.List(CriteriaImpl criteria, IList results) 
    at NHibernate.Impl.CriteriaImpl.List(IList results) 
    at NHibernate.Impl.CriteriaImpl.List[T]() 
    at NHibernate.Criterion.QueryOver`1.List() 
    at NHibernate.Criterion.QueryOver`1.NHibernate.IQueryOver<TRoot>.List() 
    at At2ClaimBO.Src.Repositories.UserRepo.GetUsers(String searchStr, Int32 roleId, Int32 page) in D:\Arunsawad\At2ClaimBO\At2ClaimBO\Src\Repositories\UserRepo.cs:line 85 
    at At2ClaimBO.Src.Services.ClaimService.GetUsers(String searchStr, Int32 roleLevel, Int32 page) in D:\Arunsawad\At2ClaimBO\At2ClaimBO\Src\Services\ClaimService.cs:line 1326 
    at At2ClaimBO.Controllers.AdminController.SearchHead(String search_str, String role_id, Int32 page) in D:\Arunsawad\At2ClaimBO\At2ClaimBO\Controllers\AdminController.cs:line 259 
    at lambda_method(Closure , ControllerBase , Object[]) 
    at System.Web.Mvc.ActionMethodDispatcher.Execute(ControllerBase controller, Object[] parameters) 
    at System.Web.Mvc.ReflectedActionDescriptor.Execute(ControllerContext controllerContext, IDictionary`2 parameters) 
    at System.Web.Mvc.ControllerActionInvoker.InvokeActionMethod(ControllerContext controllerContext, ActionDescriptor actionDescriptor, IDictionary`2 parameters) 
    at System.Web.Mvc.Async.AsyncControllerActionInvoker.<>c__DisplayClass42.<BeginInvokeSynchronousActionMethod>b__41() 
    at System.Web.Mvc.Async.AsyncResultWrapper.<>c__DisplayClass8`1.<BeginSynchronous>b__7(IAsyncResult _) 
    at System.Web.Mvc.Async.AsyncResultWrapper.WrappedAsyncResult`1.End() 
    at System.Web.Mvc.Async.AsyncControllerActionInvoker.EndInvokeActionMethod(IAsyncResult asyncResult) 
    at System.Web.Mvc.Async.AsyncControllerActionInvoker.<>c__DisplayClass37.<>c__DisplayClass39.<BeginInvokeActionMethodWithFilters>b__33() 
    at System.Web.Mvc.Async.AsyncControllerActionInvoker.<>c__DisplayClass4f.<InvokeActionMethodFilterAsynchronously>b__49() 

Answer 1

NHibernate的本身并不支持这一点 - 你将不得不使用类似的表值函数和SQL查询：

假设您使用的是MSSQL服务器，并且支持表值函数的版本（可能是2008以后？）：

SQL函数：

CREATE FUNCTION fnGetParents(@id INT) 
    RETURNS @tbl TABLE (ID INT NOT NULL) 
    AS 
BEGIN  
    ;WITH t AS (
     SELECT ParentId AS Id 
     FROM Hierarchy 
     WHERE Id = @id 
     UNION ALL 
     SELECT ParentId 
     FROM Hierarchy 
     INNER JOIN t ON t.Id = Hierarchy.Id 
    ) 
    INSERT INTO @tbl 
    SELECT DISTINCT Id FROM t 
    WHERE Id IS NOT NULL 

    RETURN; 
END 

，然后得到的结果：

session.CreateSQLQuery("SELECT Id FROM dbo.fnGetParents(:id)") 
    .SetInt32("id", id) 
    .List<int>(); 

如果你想将其包含在标准或QueryOver功能，您可以使用SQLCriteria或SQLProjection，如：

var hierarchyQuery = new SQLCriterion(
          new SqlString("{alias}.id IN (SELECT Id FROM dbo.fnGetParents(?))"), 
          new object[] {id}, 
          new[] {NHibernateUtil.Int32}); 
var results = session.QueryOver<Hierarchy>() 
      .Where(hierarchyQuery) 
      .List();