删除和插入事务仍导致违反c#

我一直在运行一个应用程序，刚刚查看了它产生的错误日志。由于主键冲突，我收到多个错误。看过执行该操作的源代码后，我无法理解为什么会发生这种情况

该应用程序是用C#on Dotnet Core编写的，不使用ORM框架，而是使用

SqlObjects

该命令使用

DbCommand

事务更新表。正如我所说的，即使命令本身在使用更新的时间重新提交之前删除了条目，我也会遇到主键冲突。我似乎无法理解为什么会出现这种情况，特别是当SqlCommand应该是一个事务时

命令

_sqlObjectFactory.GetConnection()
    .Using(connection =>
    {
        var command = connection.Command(
                _sqlObjectFactory, "DELETE FROM pf_ServiceHeartbeat WHERE ServiceName = @ServiceName AND MachineName = @MachineName")
            .AddParameter(_sqlObjectFactory, "@ServiceName", serviceName)
            .AddParameter(_sqlObjectFactory, "@MachineName", machineName);
        command.ExecuteNonQuery();
        command.CommandText = "INSERT INTO pf_ServiceHeartbeat (ServiceName, MachineName, LastRun) VALUES (@ServiceName, @MachineName, @LastRun)";
        command.AddParameter(_sqlObjectFactory, "@LastRun", lastRun);
        command.ExecuteNonQuery();
    });

错误日志

Error: 11/07/2017 12:50:20 - SqlException: Violation of PRIMARY KEY constraint 'PK_pf_ServiceHeartbeat'. Cannot insert duplicate key in object 'dbo.pf_ServiceHeartbeat'. The duplicate key value is (PopForums.Email.EmailApplicationService, MACHINENAME).
The statement has been terminated.
at System.Data.SqlClient.SqlConnection.OnError(SqlException exception, Boolean breakConnection, Action`1 wrapCloseInAction)
at System.Data.SqlClient.TdsParser.ThrowExceptionAndWarning(TdsParserStateObject stateObj, Boolean callerHasConnectionLock, Boolean asyncClose)
at System.Data.SqlClient.TdsParser.TryRun(RunBehavior runBehavior, SqlCommand cmdHandler, SqlDataReader dataStream, BulkCopySimpleResultSet bulkCopyHandler, TdsParserStateObject stateObj, Boolean& dataReady)
at System.Data.SqlClient.SqlCommand.FinishExecuteReader(SqlDataReader ds, RunBehavior runBehavior, String resetOptionsString)
at System.Data.SqlClient.SqlCommand.RunExecuteReaderTds(CommandBehavior cmdBehavior, RunBehavior runBehavior, Boolean returnStream, Boolean async, Int32 timeout, Task& task, Boolean asyncWrite, SqlDataReader ds)
at System.Data.SqlClient.SqlCommand.InternalExecuteNonQuery(TaskCompletionSource`1 completion, Boolean sendToPipe, Int32 timeout, Boolean asyncWrite, String methodName)
at System.Data.SqlClient.SqlCommand.ExecuteNonQuery()
at PopForums.Data.Sql.Repositories.ServiceHeartbeatRepository.<>c__DisplayClass3_0.b__0(DbConnection connection) in E:\Projects\Forum\src\PopForums.Sql\Repositories\ServiceHeartbeatRepository.cs:line 40
at PopForums.Data.Sql.Extensions.Using(DbConnection connection, Action`1 action) in E:\Projects\Forum\src\PopForums.Sql\Extensions.cs:line 53
at PopForums.Data.Sql.Repositories.ServiceHeartbeatRepository.RecordHeartbeat1(String serviceName, String machineName, DateTime lastRun) in E:\Projects\Forum\src\PopForums.Sql\Repositories\ServiceHeartbeatRepository.cs:line 32
at PopForums.Services.ServiceHeartbeatService.Add(String serviceName, String machineName) in E:\Projects\Forum\src\PopForums\Services\ServiceHeartbeatService.cs:line 37
at PopForums.Services.ServiceHeartbeatService.RecordHeartbeat(String serviceName, String machineName) in E:\Projects\Forum\src\PopForums\Services\ServiceHeartbeatService.cs:line 25
at PopForums.Services.ApplicationServiceBase.Execute(Object sender) in E:\Projects\Forum\src\PopForums\Services\ApplicationServiceBase.cs:line 50

HelpLink.ProdName: Microsoft SQL Server
HelpLink.ProdVer: 13.00.4422
HelpLink.EvtSrc: MSSQLServer
HelpLink.EvtID: 2627
HelpLink.BaseHelpUrl: http://go.microsoft.com/fwlink
HelpLink.LinkId: 20476

---

我复制了你的情况，除了谷歌沉默的

SqlObjects

SQL Server 2017预览版，在Ubuntu 16.04上

CREATE TABLE test.dbo.pf_ServiceHeartbeat (
    ServiceName nvarchar(256) NOT NULL,
    MachineName nvarchar(256) NOT NULL,
    LastRun datetime NOT NULL,
    CONSTRAINT PK_pf_ServiceHeartbeat PRIMARY KEY (ServiceName,MachineName)
)

var scsb = new SqlConnectionStringBuilder();
scsb.Password="....";
scsb.UserID="sa";
scsb.DataSource="localhost";
scsb.InitialCatalog="test";
using(SqlConnection conn = new SqlConnection(scsb.ConnectionString)) 
{
    conn.Open();
    using(var tran=conn.BeginTransaction()) {
        using(var comm = new SqlCommand("DELETE FROM pf_ServiceHeartbeat WHERE ServiceName = @ServiceName AND MachineName = @MachineName", conn, tran)) {
            comm.Parameters.AddWithValue("@ServiceName", "PopForums.Email.EmailApplicationService");
            comm.Parameters.AddWithValue("@MachineName", "MACHINENAME");
            comm.ExecuteNonQuery();
            comm.CommandText="INSERT INTO pf_ServiceHeartbeat (ServiceName, MachineName, LastRun) VALUES (@ServiceName, @MachineName, @LastRun)";
            comm.Parameters.AddWithValue("@LastRun", DateTime.Now);
            comm.ExecuteNonQuery();
        }
        tran.Commit();
    }
}

项目（csproj）文件：

无论是否使用事务，每次运行都可以正常运行

---

因为我看不出与使用

SqlObjects

实现有什么不同，也许您应该尝试直接使用ADO.NET？导致错误的中间级别更少。

共享表定义和

PK\u pf\u ServiceHeartbeat的定义。没有这些信息，这只是猜测。“重复的键值是（PopForums.Email.EmailApplicationService，MACHINENAME）。”它说MACHINENAME是PK。检查表定义。为列
MACHINENAME
选择一个唯一值。您插入的名称在此列中已经存在。@ARr0w应用程序正在同一台计算机上运行，因此delete语句应该已将其删除。是否应该？将参数重新应用于insert语句您尚未将主键设置为群集？如果您这样做了，会有什么不同吗？默认情况下，MSSQL会将主键创建为聚集索引<因此，代码>聚集

是多余的。在不使用的情况下尝试它，然后使用DBeaver检查它是聚集索引还是非聚集索引。不管怎样，它是有效的。

<Project Sdk="Microsoft.NET.Sdk">
  <PropertyGroup>
    <OutputType>Exe</OutputType>
    <TargetFramework>netcoreapp2.0</TargetFramework>
  </PropertyGroup>
  <ItemGroup>
    <PackageReference Include="System.Data.Common" Version="4.3.0" />
    <PackageReference Include="System.Data.SqlClient" Version="4.3.1" />
  </ItemGroup>
</Project>

var scsb = new SqlConnectionStringBuilder();
scsb.Password="....";
scsb.UserID="sa";
scsb.DataSource="localhost";
scsb.InitialCatalog="test";
using(SqlConnection conn = new SqlConnection(scsb.ConnectionString)) 
{
    conn.Open();
    using(var tran=conn.BeginTransaction()) {
        using(var comm = new SqlCommand("DELETE FROM pf_ServiceHeartbeat WHERE ServiceName = @ServiceName AND MachineName = @MachineName", conn, tran)) {
            comm.Parameters.AddWithValue("@ServiceName", "PopForums.Email.EmailApplicationService");
            comm.Parameters.AddWithValue("@MachineName", "MACHINENAME");
            comm.ExecuteNonQuery();
            comm.CommandText="INSERT INTO pf_ServiceHeartbeat (ServiceName, MachineName, LastRun) VALUES (@ServiceName, @MachineName, @LastRun)";
            comm.Parameters.AddWithValue("@LastRun", DateTime.Now);
            comm.ExecuteNonQuery();
        }
        tran.Commit();
    }
}