[英]Nhibernate - Getting Exception executing SQL Query
我正在使用Nhibernate執行SQL查詢,下面是我用於此的代碼:
public ArrayList getDocumentsForApproval(string ReleaseId)
{
string query = string.Format("SELECT distinct doc.Id, doc.Name as Doc, doc.url as url, suser.Name as Author, ds.name, CONVERT(VARCHAR(11), doc.DateEntered, 101) as DateEntered FROM dbo.Documents doc INNER JOIN DevelopmentSteps ds ON doc.TypeId = ds.Id INNER JOIN DocumentTrackingItems dti ON doc.Id = dti.DocumentId INNER JOIN TrackingItems ti ON dti.ItemStepId = ti.Id INNER JOIN dbo.Releases rl ON ti.ReleaseId = rl.BugTrackerName left outer join (select * from users) as suser on doc.AuthorUserid = suser.Id WHERE doc.DateEntered IS NOT NULL AND doc.DateApproved IS NULL AND rl.ID = '{0}'", ReleaseId);
ISession session = NHibernateHelper.GetCurrentSession();
ArrayList document =(ArrayList) session.CreateSQLQuery(query).List();
return document;
}
我收到的錯誤信息如下:
**Exception Details:**
NHibernate.QueryException: Return types of SQL query were not specified [SELECT distinct doc.Id, doc.Name as Doc, doc.url as url, suser.Name as Author, ds.name, CONVERT(VARCHAR(11), doc.DateEntered, 101)
可能是什么問題? - - 謝謝
你從根本上誤解了NHibernate。 NHibernate與TypeDataSource類不同,它返回的是不是真正業務對象的DataSets / DataTables。
NHibernate旨在使用完全擁有的對象,因此您可以使用類似的東西
Public Class Document
{
public virtual decimal Id { get; set; }
public virtual string Name { get; set; }
public virtual DateTime DateEntered { get; set; }
... so forth
}
然后,您需要手動或通過代碼生成創建映射文件以用於原始HBM映射,或者使用NH之上的工具以編程方式使用FluentNHibernate或ConfORM構建映射。
在嘗試查詢之前,您需要學習NHibernate的基礎知識,這是一個不錯的介紹性帖子: http : //www.fincher.org/tips/Languages/NHibernate.shtml
然后查詢您可以使用http://www.castleproject.org/ActiveRecord/documentation/v1rc1/usersguide/hql.html作為參考。
在大多數情況下,您應該使用實體對象而不是自定義查詢。 如果您確實需要自定義查詢,則以下示例可能很有用
public IEnumerable<GeoAreaIdAndCode> ReadAllGssCodes()
{
var query = "select GeoAreaID,Code from GeoAreaAlternativeCode where AlternativeCodeType=" + (int)GeoAreaAlternativeCodeType.GssCode;
var result = Owner.Session.CreateSQLQuery(query)
.AddScalar("GeoAreaID",NHibernateUtil.Int32)
.AddScalar("Code",NHibernateUtil.String)
.SetResultTransformer(Transformers.AliasToBean(typeof (GeoAreaIdAndCode)))
.List<GeoAreaIdAndCode>();
return result;
}
public class GeoAreaIdAndCode
{
public int GeoAreaID { get; set; }
public string Code { get; set; }
}
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