NHibernate 连接查询抛出错误

Question

我正在尝试实现一个连接查询。我需要获取列 id 的名称

string hql = "select new TerminalStateReportItem(p.Ip, p.Error, p.Terminal_Id, p.Last_Activity, p.Current_Page, p.Ping, u.Name) from TerminalState p join User u on p.Terminal_Id=u.Id";
var query = new SimpleQuery<TerminalStateReportItem>(hql);
return query.Execute();

我收到一个错误

Castle.ActiveRecord.Framework.ActiveRecordException: 无法为 TerminalStateReportItem 执行 ExecuteQuery ---> NHibernate.Hql.Ast.ANTLR.SemanticException: 路径需要加入！ [select new TerminalStateReportItem(p.Ip, p.Error, p.Terminal_Id, p.Last_Activity, p.Current_Page, p.Ping, u.Name) from KioskServer.TerminalState.TerminalState p join User1 u on p.Terminal_Id=u。编号]

我的类包装器

namespace KioskServer.Reports
{
    [ActiveRecord]
    public class TerminalStateReportItem
    {
        public TerminalStateReportItem()
        {
        }

        public TerminalStateReportItem(string ip, string error, int terminalId, DateTime lastActivity, string currentPage, int ping, string name)
        {
            Ip = ip;
            Error = error;
            Terminal_Id = terminalId;
            Last_Activity = lastActivity;
            Current_Page = currentPage;
            Ping = ping;
            Name = name;
        }

        [PrimaryKey]
        public string Ip { get; set; }
        public string Error { get; set; }
        public int Terminal_Id { get; set; }
        public DateTime Last_Activity { get; set; }
        public string Current_Page { get; set; }
        public int Ping { get; set; }
        public string Name{ get; set; }
    }
}

我的班级表

namespace KioskServer.TerminalState
{
    [ActiveRecord("terminal_state")]
    public class TerminalState
    {
        public TerminalState(){
        }

        public TerminalState(string ip, string error, int terminalId, DateTime lastActivity, string currentPage, int ping)
        {
            Ip = ip;
            Error = error;
            Terminal_Id = terminalId;
            Last_Activity = lastActivity;
            Current_Page = currentPage;
            Ping = ping;
        }

        [PrimaryKey]
        public string Ip { get; set; }
        [Property]
        public string Error { get; set; }
        [Property]
        public int Terminal_Id { get; set; }
        [Property]
        public DateTime Last_Activity { get; set; }
        [Property]
        public string Current_Page { get; set; }
        [Property]
        public int Ping { get; set; }
    }
}

不加入所有作品都正常。可能是因为我的课程在不同的文件夹中？

namespace KioskServer.Data.Users
{
    [ActiveRecord("users",
        DiscriminatorColumn = "usertype",
        DiscriminatorType = "string",
        DiscriminatorValue = "user")]
    public class User : Entity
    {
        [Property]
        public string Name { get; set; }

        [Property]
        public string Login { get; set; }

        [Property]
        public string Password { get; set; }

        [Property]
        public DateTime Date { get; set; }

        [BelongsTo]
        public Dealer Dealer { get; set; }
    }
}

我做一个查询

string hql = "select new TerminalStateItem(p.Ip, p.Error, p.Terminal_Id, p.Last_Activity, p.Current_Page, p.Ping, u.Name) from TerminalState p join p.User u";

错误

NHibernate.QueryException: could not resolve property: User of: KioskServer.TerminalState.TerminalState [select new TerminalStateItem(p.Ip, p.Error, p.Terminal_Id, p.Last_Activity, p.Current_Page, p.Ping, u.Name) from KioskServer.TerminalState.TerminalState p join p.User u]

Answer 1

HQL 是一种在您的领域模型上运行的语言。它不是 SQL。这是什么意思？

在 SQL 中你可以说：

SELECT **
FROM  TerminalState p   -- (table TerminalState)
JOIN User1 u            -- (table User1)
ON p.Terminal_Id = u.Id -- (the relation   

在 HQL 中你不能！因为 ON 是由关系定义的……由 path 定义。所以这里的 Exception 说：

预期加入的路径！

域关系，对象之间的路径，例如这将在 HQL 中工作：

select new p.Ip, u.Name ...
from TerminalState p 
// now the PATH
join p.User u  // not needed on p.Terminal_Id=u.Id";

ON（NHibernate 生成的 SQL 语法没有我们的明确定义） 必须来自映射。 TerminalState 上必须有 User 属性映射为 many-to-one...

在这里查看更多：

• 14. HQL: The Hibernate Query Language
• 14.3. Associations and joins

如果你需要一些特殊的 SQL，你仍然可以使用 NHibernate 来获取它，只需使用：

session.CreateSQLQuery() // could contain any valid SQL

而不是session.CreateQuery() （期待 HQL）

Answer 2

你应该有一个映射
[财产] 公共用户用户{获取；放; }

在类 TerminalStateReportItem 中

然后就可以查询了。