读取位时，SqlDataReader的强制转换异常无效
本文关键字：转换 异常 无效 SqlDataReader 读取 | 更新日期: 2023-09-27 17:50:59
我有几个存储过程，它们读取相同的表并以相同的布局返回数据。其中一个存储过程在存储为位的字段上导致无效强制转换异常。SqlDataReader认为自己是int32。
create table dbo.SampleTable
(
Id INT NOT NULL IDENTITY(1,1),
SomeText VARCHAR(40),
BoolValue BIT
)
示例存储过程
create proc SampleProcedure
as
select Id,
SomeText,
BoolValue
go
示例扩展类
using System;
using System.Data.SqlClient;
namespace SampleApp.Extensions{
public static class SampleModelExtension{
private const int INDEX_ID = 0;
private const int INDEX_SOMETEXT = 1;
private const int INDEX_BOOLVALUE = 2;
public static SampleModel ToSampleModel(this SqlDataReader rdr){
SampleModel myModel = new SampleModel();
myModel.Id = !rdr.IsDbNull(INDEX_ID) ? rdr.GetInt32(INDEX_ID) : 0;
myModel.SomeText = !rdr.IsDbNull(INDEX_SOMETEXT) ? rdr.GetString(INDEX_SOMETEXT) : String.Empty;
myModel.Boolvalue = !rdr.IsDbNull(INDEX_BOOLVALUE) ? rdr.GetBool(INDEX_BOOLVALUE) : false;
return myModel;
}
}
}
样本库类
using SampleApp.Extensions;
using System;
using System.Collections.Generic;
using System.Data.SqlCient;
namespace SampleApp {
public SampleRepository : BaseDataConnection {
public List<SampleModel> GetSampleData(){
SqlCommand cmd = new SqlCommand("SampleProcedure", base.Connection);
List<SampleModel> retVal = new List<SampleModel>();
using(SqlDataReader rdr = base.GetDataReader(cmd)){
while(rdr.Read()){
retVal.Add(rdr.ToSampleModel());
}
}
return retVal;
}
public List<SampleModel> GetMoreSampleData(){
SqlCommand cmd = new SqlCommand("AnotherSampleProcedure", base.Connection);
List<SampleModel> retVal = new List<SampleModel>();
using(SqlDataReader rdr = base.GetDataReader(cmd)){
while(rdr.Read()){
retVal.Add(rdr.ToSampleModel());
}
}
return retVal;
}
}
}
这是一个类似于我的设置。在我的代码中，我有一个扩展方法，它将把SqlDataReader转换为SampleModel的类型，以便在存储库类中的所有加载方法中重用扩展方法。正是因为这种方法，我知道它可以与所有其他方法一起工作。
你知道为什么它会把列看作int而不是bit吗?
实际存储过程
ALTER PROCEDURE [dbo].[GetAllActiveScheduledEventsByDateRange]
@SiteGuid VARCHAR(38),
@StartDate DATE,
@EndDate DATE
AS
SELECT se.EventId,
se.AvailableDate,
se.StartTime,
se.NumberOfPatrons,
se.AgeOfPatrons,
se.ContactEmailAddress,
se.ContactPhone,
se.ContactName,
se.EventTypeId,
se.PartyName,
se.ConfirmationDateTime,
se.ReminderDateTime,
se.UserComments,
se.AdminComments,
se.Active,
se.CheckInTime,
se.CheckOutTime,
se.GunSize,
(
Select Count(p.playerid) from
(select * from waiver2 where waiverid in (
(Select WaiverId
from Waiver2
inner join
(
Select max(CreateDateTime) as LatestDate, PlayerId
from Waiver2
WHERE siteguid = @SiteGuid
Group by PlayerId
) SubMax
on Waiver2.CreateDateTime = SubMax.LatestDate
and Waiver2.PlayerId = SubMax.PlayerId))) w,
player p, PlayDateTime updt
where p.playerid = w.playerid
and p.playerid = updt.PlayerId
and updt.EventId = se.EventId) AS WaiverCount,
se.DepositAmount,
se.CreateDateTime,
se.PaymentReminderDateTime,
se.PaymentStatusId,
se.PackageId
FROM ScheduledEvent se
WHERE se.SiteGuid = @SiteGuid
AND se.AvailableDate BETWEEN @StartDate AND @EndDate
AND se.PaymentStatusId < '99'
AND se.Active = 1
ORDER BY se.StartTime, se.ContactName
抛出错误的是Active列。它被定义为BIT，并作为第14列索引。
导致问题的实际存储过程
ALTER proc [dbo].[W2_GetAllActiveScheduledEventsByDateWithWaivers]
@SiteGuid VARCHAR(38),
@AvailableDate DATE
AS
SELECT se.EventId,
se.AvailableDate,
se.StartTime,
se.NumberOfPatrons,
se.AgeOfPatrons,
se.ContactEmailAddress,
se.ContactPhone,
se.ContactName,
se.EventTypeId,
se.PartyName,
se.ConfirmationDateTime,
se.ReminderDateTime,
se.UserComments,
se.AdminComments,
se.Active,
se.CheckInTime,
se.CheckOutTime,
se.GunSize,
(
Select Count(p.playerid) from
(
select * from waiver2 where waiverid in
(
(
Select WaiverId
from Waiver2
inner join
(
Select max(CreateDateTime) as LatestDate, PlayerId
from Waiver2
WHERE siteguid = @SiteGuid
Group by PlayerId
) SubMax
on Waiver2.CreateDateTime = SubMax.LatestDate
and Waiver2.PlayerId = SubMax.PlayerId
and DateDiff(year,Waiver2.CreateDateTime,GETDATE()) = 0
)
)
) w,
player p, PlayDateTime updt
where p.playerid = w.playerid
and p.playerid = updt.PlayerId
and updt.EventId = se.EventId
and ((
FLOOR(DATEDIFF(day,p.DateOfBirth,GETDATE())/365.242199) >= 18
and
w.ParentId is null
)
or
(
FLOOR(DATEDIFF(day,p.DateOfBirth,GETDATE())/365.242199) < 18
and
w.ParentId is not null
))
) AS WaiverCount,
se.DepositAmount,
se.CreateDateTime,
se.PaymentReminderDateTime,
se.PaymentStatusId,
se.PackageId
FROM ScheduledEvent se
WHERE se.SiteGuid = @SiteGuid
AND se.AvailableDate = @AvailableDate
AND se.PaymentStatusId <= '90'
AND se.Active = 1
--ORDER BY se.StartTime, se.ContactName
union select null,
pdt.PlayDate,
pdt.PlayTime,
null,
null,
null,
null,
null,
null,
'Walk-up Players',
null,
null,
null,
null,
1,
null,
null,
null,
COUNT('x') AS WaiverCount,
0,
null,
null,
null,
null
from PlayDateTime pdt
where pdt.PlayDate = @AvailableDate
and pdt.EventId is null
and pdt.PlayerId in (
Select p.playerid from
(select * from waiver2 where waiverid in (
(Select WaiverId
from Waiver2
inner join
(
Select max(CreateDateTime) as LatestDate, PlayerId
from Waiver2
WHERE siteguid = @SiteGuid
Group by PlayerId
) SubMax
on Waiver2.CreateDateTime = SubMax.LatestDate
and Waiver2.PlayerId = SubMax.PlayerId
and DateDiff(year,Waiver2.CreateDateTime,GETDATE()) = 0))) w,
player p
where p.playerid = w.playerid
and ((
FLOOR(DATEDIFF(day,p.DateOfBirth,GETDATE())/365.242199) >= 18
and
w.ParentId is null
)
or
(
FLOOR(DATEDIFF(day,p.DateOfBirth,GETDATE())/365.242199) < 18
and
w.ParentId is not null
))
)
group by pdt.PlayDate, pdt.PlayTime
order by 2, 3, 10
这是实际的扩展类(为了保护无辜而更改了名称)
namespace MyNameSpace.Svc.Core.Extensions.Registration {
public static class ScheduledEventExtension {
#region attributes
private const int INDEX_ID = 0;
private const int INDEX_DATE = 1;
private const int INDEX_STARTTIME = 2;
private const int INDEX_NUMBEROFPATRONS = 3;
private const int INDEX_AGEOFPATRONS = 4;
private const int INDEX_CONTACTEMAIL = 5;
private const int INDEX_CONTACTPHONE = 6;
private const int INDEX_CONTACTNAME = 7;
private const int INDEX_EVENTTYPE = 8;
private const int INDEX_PARTYNAME = 9;
private const int INDEX_CONFIRMDATE = 10;
private const int INDEX_REMINDDATE = 11;
private const int INDEX_USERCOMMENTS = 12;
private const int INDEX_ADMINCOMMENTS = 13;
private const int INDEX_ACTIVE = 14;
private const int INDEX_CHECKINTIME = 15;
private const int INDEX_CHECKOUTTIME = 16;
private const int INDEX_GUNSIZE = 17;
private const int INDEX_WAIVERCOUNT = 18;
private const int INDEX_DEPOSITAMOUNT = 19;
private const int INDEX_CREATEDATETIME = 20;
private const int INDEX_PAYMENTREMINDERDATETIME = 21;
private const int INDEX_PAYMENTSTATUS = 22;
private const int INDEX_PACKAGEID = 23;
#endregion
#region methods
public static ScheduledEvent ToScheduledEvent(this SqlDataReader rdr) {
ScheduledEvent retVal = new ScheduledEvent();
retVal.Id = !rdr.IsDBNull(INDEX_ID) ? rdr.GetInt32(INDEX_ID) : 0;
retVal.SelectedDate.SelectedDate = !rdr.IsDBNull(INDEX_DATE) ? rdr.GetDateTime(INDEX_DATE) : DateTime.MinValue;
retVal.SelectedDate.StartTime = !rdr.IsDBNull(INDEX_STARTTIME) ? rdr.GetTimeSpan(INDEX_STARTTIME) : TimeSpan.MinValue;
int numOfPatrons = 0;
int.TryParse(rdr.GetString(INDEX_NUMBEROFPATRONS), out numOfPatrons);
retVal.NumberOfPatrons = numOfPatrons;
retVal.AgeOfPatrons = !rdr.IsDBNull(INDEX_AGEOFPATRONS) ? rdr.GetString(INDEX_AGEOFPATRONS) : string.Empty;
retVal.ContactEmailAddress = !rdr.IsDBNull(INDEX_CONTACTEMAIL) ? rdr.GetString(INDEX_CONTACTEMAIL) : string.Empty;
retVal.ContactPhone = !rdr.IsDBNull(INDEX_CONTACTPHONE) ? rdr.GetString(INDEX_CONTACTPHONE) : string.Empty;
retVal.ContactName = !rdr.IsDBNull(INDEX_CONTACTNAME) ? rdr.GetString(INDEX_CONTACTNAME) : string.Empty;
// event type is obsolete
retVal.PartyName = !rdr.IsDBNull(INDEX_PARTYNAME) ? rdr.GetString(INDEX_PARTYNAME) : string.Empty;
retVal.ConfirmationDateTime = !rdr.IsDBNull(INDEX_CONFIRMDATE) ? rdr.GetDateTime(INDEX_CONFIRMDATE) : DateTime.MinValue;
retVal.ReminderDateTime = !rdr.IsDBNull(INDEX_REMINDDATE) ? rdr.GetDateTime(INDEX_REMINDDATE) : DateTime.MinValue;
retVal.Comments = !rdr.IsDBNull(INDEX_USERCOMMENTS) ? rdr.GetString(INDEX_USERCOMMENTS) : string.Empty;
retVal.AdminComments = !rdr.IsDBNull(INDEX_ADMINCOMMENTS) ? rdr.GetString(INDEX_ADMINCOMMENTS) : string.Empty;
retVal.Active = !rdr.IsDBNull(INDEX_ACTIVE) ? rdr.GetBoolean(INDEX_ACTIVE) : false;
retVal.CheckInDateTime = !rdr.IsDBNull(INDEX_CHECKINTIME) ? rdr.GetDateTime(INDEX_CHECKINTIME) : DateTime.MinValue;
retVal.CheckOoutDateTime = !rdr.IsDBNull(INDEX_CHECKOUTTIME) ? rdr.GetDateTime(INDEX_CHECKOUTTIME) : DateTime.MinValue;
// gun size is obsolete
retVal.WaiverCount = !rdr.IsDBNull(INDEX_WAIVERCOUNT) ? rdr.GetInt32(INDEX_WAIVERCOUNT) : 0;
retVal.DepositAmount = !rdr.IsDBNull(INDEX_DEPOSITAMOUNT) ? rdr.GetDecimal(INDEX_DEPOSITAMOUNT) : 0;
retVal.CreateDateTime = !rdr.IsDBNull(INDEX_CREATEDATETIME) ? rdr.GetDateTime(INDEX_CREATEDATETIME) : DateTime.MinValue;
retVal.PaymentReminderDateTime = !rdr.IsDBNull(INDEX_PAYMENTREMINDERDATETIME) ? rdr.GetDateTime(INDEX_PAYMENTREMINDERDATETIME) : DateTime.MinValue;
retVal.PaymentStatus = !rdr.IsDBNull(INDEX_PAYMENTSTATUS) ? PaymentStatusExtension.ToPaymentStatusEnum(rdr.GetString(INDEX_PAYMENTSTATUS)) : PaymentStatusEnum.Unpaid;
retVal.SelectedPackage.Id = !rdr.IsDBNull(INDEX_PACKAGEID) ? rdr.GetInt32(INDEX_PACKAGEID) : 0;
return retVal;
}
#endregion
}
}
这是我的存储库类(再次进行了少量修改)
using MyNameSpace.Svc.Core.Extensions;
using MyNameSpace.Svc.Core.Extensions.Registration;
using MyNameSpace.Svc.Core.Interfaces.Registration;
using MyNameSpace.Svc.Core.Models.Registration;
using System;
using System.Collections.Generic;
using System.Data.SqlClient;
namespace MyNameSpace.Svc.Impl.Repositories.Registration {
public class ScheduledEventRepositoryImpl : DatabaseConnection, IScheduledEventRepository {
#region attributes
private const string PARMNAME_RETURN = "retval";
private const string PARMNAME_ID = "EventId";
private const string PARMNAME_GUID = "SiteGuid";
private const string PARMNAME_AVAILABLEDATE = "AvailableDate";
private const string PARMNAME_STARTTIME = "StartTime";
private const string PARMNAME_NUMPATRONS = "NumberOfPatrons";
private const string PARMNAME_AGEPATRONS = "AgeOfPatrons";
private const string PARMNAME_CONTACTEMAIL = "ContactEmailAddress";
private const string PARMNAME_CONTACTPHONE = "ContactPhone";
private const string PARMNAME_CONTACTNAME = "ContactName";
private const string PARMNAME_PARTYNAME = "PartyName";
private const string PARMNAME_CONFDATE = "ConfirmationDateTime";
private const string PARMNAME_REMINDDATE = "ReminderDateTime";
private const string PARMNAME_USERCOMMENTS = "UserComments";
private const string PARMNAME_ADMINCOMMENTS = "AdminComments";
private const string PARMNAME_CHECKINTIME = "CheckInTime";
private const string PARMNAME_CHECKOUTTIME = "CheckOutTime";
private const string PARMNAME_DEPOSITAMT = "DepositAmount";
private const string PARMNAME_CREATEDATE = "CreateDateTime";
private const string PARMNAME_PAYMENTREMINDDATE = "PaymentReminderDateTime";
private const string PARMNAME_PAYMENTSTATUS = "PaymentStatusId";
private const string PARMNAME_PKGID = "PackageId";
private const string PARMNAME_EMAIL = "EmailAddress";
private const string PARMNAME_DAYSOUT = "DaysOut";
private const string PARMNAME_EVENTTYPE = "EventTypeId";
private const string PARMNAME_STARTDATE = "StartDate";
private const string PARMNAME_ENDDATE = "EndDate";
private const string SPNAME_GETALLACTIVEBYDATERANGE = "GetAllActiveScheduledEventsByDateRange";
private const string SPNAME_GETALLACTIVEBYDATEWITHWAIVERS = "W2_GetAllActiveScheduledEventsByDateWithWaivers";
#endregion
#region methods
public List<ScheduledEvent> GetAllActiveScheduledEventsByDateRange(Guid siteGuid, DateTime startDate, DateTime endDate) {
List<ScheduledEvent> retVal = new List<ScheduledEvent>();
SqlCommand cmd = new SqlCommand(SPNAME_GETALLACTIVEBYDATERANGE, base.Connection);
cmd.Parameters.AddWithValue(PARMNAME_GUID, siteGuid.ToFormattedString());
cmd.Parameters.AddWithValue(PARMNAME_STARTDATE, startDate);
cmd.Parameters.AddWithValue(PARMNAME_ENDDATE, endDate);
using(SqlDataReader rdr = base.GetDataReader(cmd)) {
while(rdr.Read()) {
retVal.Add(rdr.ToScheduledEvent());
}
}
return retVal;
}
public List<ScheduledEvent> GetAllActiveScheduledEventsByDateWithWaivers(Guid siteGuid, DateTime availableDate) {
List<ScheduledEvent> retVal = new List<ScheduledEvent>();
using(SqlDataReader rdr = base.GetDataReader(SPNAME_GETALLACTIVEBYDATEWITHWAIVERS, PARMNAME_AVAILABLEDATE, availableDate, siteGuid)) {
while(rdr.Read()) {
retVal.Add(rdr.ToScheduledEvent());
}
}
return retVal;
}
#endregion
}
}
高度怀疑" SqlDataReader认为它是int32 "。SqlDataReader只知道每个字段是什么，因为RDBMS将结果集的模式与结果集一起发送。因此，该列(或者更正确地说:结果集中的字段)是和int。
在最初的最后3个代码示例(标记为"实际")中，存储的过程在名称或参数上都与存储库类调用的过程不匹配。
现在代码示例已经更新，实际过程(如问题注释中所述)有一个UNION，其中同一列有一个被选中的字面量1。字面量1的默认类型是INT，因此，由于UNION, BIT字段被隐式转换为INT是有意义的。
如果您想看到实际情况，只需尝试下面的命令(通过sys. js窥视结果集的模式)。dm_exec_describe_first_result_set (SQL Server 2012中引入):
SELECT [system_type_name]
FROM sys.dm_exec_describe_first_result_set('SELECT CONVERT(BIT, 1) AS [BITorINT?]',
NULL, NULL);
-- bit
SELECT [system_type_name]
FROM sys.dm_exec_describe_first_result_set('SELECT 1 AS [BITorINT?]', NULL, NULL);
-- int
SELECT [system_type_name]
FROM sys.dm_exec_describe_first_result_set('SELECT CONVERT(BIT, 1) AS [BITorINT?]
UNION ALL
SELECT 1', NULL, NULL);
-- int
下次提示:
- 在SSMS中运行进程，自己看看每个字段返回什么。
- 再次检查表的列定义
sql server内部将位值转换为微型int，因此使用联合将尝试求值并确定这两个值现在是这种数据类型
1和null将导致一个int数据类型最有可能是