gpt4 book ai didi

linq - Nhibernate LINQ DateTime.AddDay 不起作用

转载 作者:行者123 更新时间:2023-12-04 06:25:57 24 4
gpt4 key购买 nike

我需要在 linq 查询中比较两个 DateTime 属性,类似于
下面那个——

var patients = from c in session.Query<Patient>() where c.DateAdded.AddDays(1) < c.AdmitDate select c;

当我运行查询时,出现此异常:
System.NotSupportedException {"System.DateTime AddDays(Double)"}


NHibernate.Linq.Visitors.HqlGeneratorExpressionTreeVisitor.VisitMethodCallExpression(MethodCallExpression
表达)

我看了一下法比奥的文章
http://fabiomaulo.blogspot.com/2010/07/nhibernate-linq-provider-exten ...
但是 treeBuilder 没有任何特定于
日期时间比较。

这是示例的代码。要运行它,请为 FluentNhibernate 和 SQLite 安装 NuGet 包。

using System;
using System.Collections.Generic;
using System.Data.SQLite;
using System.IO;
using System.Linq;
using System.Text;
using FluentNHibernate.Cfg;
using FluentNHibernate.Cfg.Db;
using FluentNHibernate.Mapping;
using NHibernate;
using NHibernate.Cfg;
using NHibernate.Tool.hbm2ddl;
using NHibernate.Linq;

namespace ConsoleApplication1
{
class Program
{
private static Configuration _config;

static void Main(string[] args)
{
var sessionFactory = CreateSessionFactory();
using (var session = sessionFactory.OpenSession())
{
BuildSchema(session);
using(var transaction = session.BeginTransaction())
{
var foo = new Patient
{
Name = "Foo",
Sex = Gender.Male,
DateAdded = new DateTime(2009, 1, 1),
AdmitDate = new DateTime(2009, 1, 2)
};
var bar = new Patient
{
Name = "Bar",
Sex = Gender.Female,
DateAdded = new DateTime(2009, 1, 1),
AdmitDate = new DateTime(2009, 1, 2)
};
session.SaveOrUpdate(foo);
session.SaveOrUpdate(bar);
transaction.Commit();
}
session.Flush();

using (session.BeginTransaction())
{
var cats = from c in session.Query<Patient>() where
c.DateAdded.AddDays(1) < c.AdmitDate select c;
foreach (var cat in cats)
{
Console.WriteLine("patient name {0}, sex {1}", cat.Name,
cat.Sex);
}
}
}
Console.ReadKey();
}

private static ISessionFactory CreateSessionFactory()
{
return Fluently.Configure()
.Database(
SQLiteConfiguration.Standard.InMemory()
)
.Mappings(m =>
m.FluentMappings.AddFromAssemblyOf<Program>())
.ExposeConfiguration(c => _config = c)
.BuildSessionFactory();
}

private static void BuildSchema(ISession session)
{
new SchemaExport(_config)
.Execute(true, true, false, session.Connection, null);
}
}

public class PatientMap : ClassMap<Patient>
{
public PatientMap()
{
Id(x => x.Id);
Map(x => x.Name)
.Length(16)
.Not.Nullable();
Map(x => x.Sex);
Map(x => x.DateAdded);
Map(x => x.AdmitDate);
}
}

public class Patient
{
public virtual int Id { get; set; }
public virtual string Name { get; set; }
public virtual Gender Sex { get; set; }
public virtual DateTime DateAdded { get; set; }
public virtual DateTime AdmitDate { get; set; }
}

public enum Gender
{
Male,
Female
}

谢谢,
维克拉姆

最佳答案

回答上述问题:

using System;
using System.Linq;
using System.Reflection;
using FluentNHibernate.Cfg;
using FluentNHibernate.Cfg.Db;
using FluentNHibernate.Mapping;
using NHibernate;
using NHibernate.Cfg;
using NHibernate.Dialect;
using NHibernate.Dialect.Function;
using NHibernate.Hql.Ast;
using NHibernate.Linq.Functions;
using NHibernate.Tool.hbm2ddl;
using NHibernate.Linq;
using System.Collections.ObjectModel;
using System.Linq.Expressions;
using NHibernate.Linq.Visitors;
using NHibernate.Cfg.Loquacious;

namespace ConsoleApplication1
{
class Program
{
private static Configuration _config;

static void Main(string[] args)
{App_Start.NHibernateProfilerBootstrapper.PreStart();

var sessionFactory = CreateSessionFactory();
using (var session = sessionFactory.OpenSession())
{
BuildSchema(session);
using(var transaction = session.BeginTransaction())
{
var foo = new Patient
{
Name = "Foo",
Sex = Gender.Male,
DateAdded = new DateTime(2009, 1, 4),
AdmitDate = new DateTime(2009, 1, 6)
};
var bar = new Patient
{
Name = "Bar",
Sex = Gender.Female,
DateAdded = new DateTime(2009, 1, 1),
AdmitDate = new DateTime(2009, 1, 2)
};
session.SaveOrUpdate(foo);
session.SaveOrUpdate(bar);
transaction.Commit();
}
session.Flush();

using (session.BeginTransaction())
{
//x.PatientVisit.AdmitDate.Value.Date == x.DateAdded.Date
var patients = from c in session.Query<Patient>() where c.DateAdded.AddDays(1) < c.AdmitDate.Value select c;
foreach (var cat in patients)
{
Console.WriteLine("patient name {0}, sex {1}", cat.Name, cat.Sex);
}
}
}
Console.ReadKey();
}

private static ISessionFactory CreateSessionFactory()
{
return Fluently.Configure()
.Database(
MsSqlConfiguration.MsSql2008.Dialect<CustomDialect>()
.ConnectionString("Data Source=.;Initial Catalog=testdb;Integrated Security=True;Connection Reset=false")
)
.Mappings(m =>
m.FluentMappings.AddFromAssemblyOf<Program>())
.ExposeConfiguration(c =>
{
c.LinqToHqlGeneratorsRegistry<ExtendedLinqtoHqlGeneratorsRegistry>();
_config = c;
})
.BuildSessionFactory();
}

private static void BuildSchema(ISession session)
{
new SchemaExport(_config)
.Execute(true, true, false, session.Connection, null);
}
}

public class PatientMap : ClassMap<Patient>
{
public PatientMap()
{
Id(x => x.Id);
Map(x => x.Name)
.Length(16)
.Not.Nullable();
Map(x => x.Sex);
Map(x => x.DateAdded);
Map(x => x.AdmitDate);
}
}

public class Patient
{
public virtual int Id { get; set; }
public virtual string Name { get; set; }
public virtual Gender Sex { get; set; }
public virtual DateTimeOffset DateAdded { get; set; }
public virtual DateTime? AdmitDate { get; set; }
}

public enum Gender
{
Male,
Female
}

public class ExtendedLinqtoHqlGeneratorsRegistry : DefaultLinqToHqlGeneratorsRegistry
{
public ExtendedLinqtoHqlGeneratorsRegistry()
{
this.Merge(new AddDaysGenerator());
}
}

public class AddDaysGenerator : BaseHqlGeneratorForMethod
{
public AddDaysGenerator()
{
SupportedMethods = new[] {
ReflectionHelper.GetMethodDefinition<DateTimeOffset?>(d => d.Value.AddDays((double)0))
};
}

public override HqlTreeNode BuildHql(MethodInfo method, Expression targetObject, ReadOnlyCollection<Expression> arguments, HqlTreeBuilder treeBuilder, IHqlExpressionVisitor visitor)
{
return treeBuilder.MethodCall("AddDays",
visitor.Visit(targetObject).AsExpression(),
visitor.Visit(arguments[0]).AsExpression()
);
}
}

public class CustomDialect : MsSql2008Dialect
{
public CustomDialect()
{
RegisterFunction(
"AddDays",
new SQLFunctionTemplate(
NHibernateUtil.DateTime,
"dateadd(day,?2,?1)"
)
);
}
}

关于linq - Nhibernate LINQ DateTime.AddDay 不起作用,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/7492311/

24 4 0
Copyright 2021 - 2024 cfsdn All Rights Reserved 蜀ICP备2022000587号
广告合作:1813099741@qq.com 6ren.com