NHibernate Criteria 查询以选择每种类型的最新项目

发布于 2024-11-09 19:08:20 字数 449 浏览 2 评论 0原文

我需要使用 NHibernate 标准查询查找工作人员提交的最新报告。我确信我需要使用投影，但我不知道如何设置它。

我的域模型的解释：

public class Employee
{
  public int Id {get; set;}
  public string Name {get; set;}
}

public class Report 
{
  public int Id {get; set;}
  public DateTime? Submitted {get; set;}
  public Employee Employee {get; set;}
  // Other report properties omitted
}

如果有 5 名员工，每人都有 7 份报告，则查询应返回 5 份报告，每个员工一份，并且 Submitted 属性不为空，并且是最近的一份报告员工。。

原文

I need to find the most recent report submitted by members of staff, using an NHibernate criteria query. I'm sure that I need to use projections, but I can't work out how to set it up.

A paraphrase of my domain model:

public class Employee
{
  public int Id {get; set;}
  public string Name {get; set;}
}

public class Report 
{
  public int Id {get; set;}
  public DateTime? Submitted {get; set;}
  public Employee Employee {get; set;}
  // Other report properties omitted
}

If there were 5 members of staff, who each have 7 reports, the query should return 5 reports, one per employee, with the Submitted property being not null, and being most recent one for that employee.

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德意的啸 2024-11-16 19:08:20

我对此不太确定，但请检查一下：

var rst = session.CreateCriteria<Report>()
                .SetProjection(Projections.GroupProperty("Employee"))
                .SetProjection(Projections.Max("Submitted"))
                .Add(NHibernate.Criterion.Expression.IsNotNull("Submitted")).List();

I am not quite sure about this, but check it out:

var rst = session.CreateCriteria<Report>()
                .SetProjection(Projections.GroupProperty("Employee"))
                .SetProjection(Projections.Max("Submitted"))
                .Add(NHibernate.Criterion.Expression.IsNotNull("Submitted")).List();

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