Question

我正在尝试为Noda Time IUserType类型创建一个NHibernate LocalTime，它将在Sql Server 2008/2012中逻辑映射到time类型。我能够从数据库中获取值和加载值。但是，我无法编写涉及当地时间比较的查询，例如_session.Query<SchedulingTemplate>().Where(x => x.Start < end && x.End >= start)会出现错误SqlException (0x80131904): The data types time and datetime are incompatible in the less than operator.

我的用户类型的相关代码是：

public Type ReturnedType
{
    get { return typeof(LocalTime); }
}

public override object NullSafeGet(IDataReader rs, string[] names, object owner)
{
    var dbValue = NHibernateUtil.Time.NullSafeGet(rs, names);
    if(dbValue == null)
        return null;

    return LocalDateTime.FromDateTime((DateTime)dbValue).TimeOfDay;
}

public override void NullSafeSet(IDbCommand cmd, object value, int index)
{
    if(value == null)
        NHibernateUtil.Time.NullSafeSet(cmd, null, index);
    else
        NHibernateUtil.Time.NullSafeSet(cmd, ((LocalTime)value).LocalDateTime.ToDateTimeUnspecified(), index);
}

public override SqlType[] SqlTypes
{
    get { return new[] { SqlTypeFactory.Time }; }
}

问题在于，尽管上面的代码表明数据库类型是时间，但它会生成以下查询（每个Sql Profiler）：

exec sp_executesql N'select [...] from [SchedulingTemplate] scheduling0_ where scheduling0_.Start<@p0 and scheduling0_.[End]>=@p1',N'@p0 datetime,@p1 datetime',@p0='1753-01-01 20:00:00',@p1='1753-01-01 06:00:00'

（注意我为了简洁省略了选择列表）

请注意，参数的类型和值被视为datetime。

这似乎与已关闭的https://nhibernate.jira.com/browse/NH-2661和https://nhibernate.jira.com/browse/NH-2660两个NH错误非常相似。

我尝试使用NHibernateUtil.TimeAsTimeSpan，但似乎也没有用。它生成了完全相同的查询，让我感到惊讶。我想也许NH-2661中描述的问题对于用户类型也存在，并且不是固定的吗？

我正在使用NHibernate v3.3.1.400和Noda Time 1.0.0-beta2

Answer 1

按照@Firo的建议，我从SqlType开始工作并想出了这个：

using NHibernate;
using NHibernate.Dialect;
using NHibernate.SqlTypes;
using NHibernate.Type;
using NodaTime;
using NodaTime.Text;
using System;
using System.Data;
using System.Data.SqlClient;

[Serializable]
public class LocalTimeType : PrimitiveType, IIdentifierType
{
    private readonly LocalTimePattern _timePattern = LocalTimePattern.CreateWithInvariantCulture("h:mm:ss tt");

    public LocalTimeType() : base(SqlTypeFactory.Time) { }

    public override string Name
    {
        get { return "LocalTime"; }
    }

    public override object Get(IDataReader rs, int index)
    {
        try
        {
            if (rs[index] is TimeSpan) //For those dialects where DbType.Time means TimeSpan.
            {
                var time = (TimeSpan)rs[index];
                return LocalTime.Midnight + Period.FromTicks(time.Ticks);
            }

            var dbValue = Convert.ToDateTime(rs[index]);
            return LocalDateTime.FromDateTime(dbValue).TimeOfDay;
        }
        catch (Exception ex)
        {
            throw new FormatException(string.Format("Input string '{0}' was not in the correct format.", rs[index]), ex);
        }
    }

    public override object Get(IDataReader rs, string name)
    {
        return Get(rs, rs.GetOrdinal(name));
    }

    public override Type ReturnedClass
    {
        get { return typeof(LocalTime); }
    }

    public override void Set(IDbCommand st, object value, int index)
    {
        var parameter = ((SqlParameter)st.Parameters[index]);
        parameter.SqlDbType = SqlDbType.Time; // HACK work around bad behavior, M$ says not ideal, but as intended, NH says this is a bug in MS may work around eventually
        parameter.Value = new TimeSpan(((LocalTime)value).TickOfDay);
    }

    public override bool IsEqual(object x, object y)
    {
        return Equals(x, y);
    }

    public override int GetHashCode(object x, EntityMode entityMode)
    {
        return x.GetHashCode();
    }

    public override string ToString(object val)
    {
        return _timePattern.Format((LocalTime)val);
    }

    public object StringToObject(string xml)
    {
        return string.IsNullOrEmpty(xml) ? null : FromStringValue(xml);
    }

    public override object FromStringValue(string xml)
    {
        return _timePattern.Parse(xml).Value;
    }

    public override Type PrimitiveClass
    {
        get { return typeof(LocalTime); }
    }

    public override object DefaultValue
    {
        get { return new LocalTime(); }
    }

    public override string ObjectToSQLString(object value, Dialect dialect)
    {
        return "'" + _timePattern.Format((LocalTime)value) + "'";
    }
}

关键代码在Set方法中，其中包含：

var parameter = ((SqlParameter)st.Parameters[index]);
parameter.SqlDbType = SqlDbType.Time;

这是必需的，因为MS数据提供商将DbType设置为DbType.Time以表示基础类型应为DateTime。您必须将 SqlDbType 设置为有效的时间。

如何在Sql Server 2008/2012中为时间创建NHibnerate IUserType？

1 个答案: