更新数据库的问题，不知错的哪里？？？

[wangchong]

Dim UpdateCnn As New Odbc.OdbcConnection
Dim tx As Odbc.OdbcTransaction
Dim Cmm As Odbc.OdbcCommand
Dim SQL As String
UpdateCnn = New Odbc.OdbcConnection(‘连接数据库’)
UpdateCnn.Open()
tx = UpdateCnn.BeginTransaction(IsolationLevel.ReadCommitted)
SQL = "update pub.yusr_mstr set yusr__chr01 = '' where yusr_name = 'qqc'"
Cmm = New Odbc.OdbcCommand(SQL, UpdateCnn)
Cmm.CommandType = CommandType.Text
Cmm.ExecuteNonQuery() ' 在这里执行半天也没做完！！！！！
tx.Commit()
UpdateCnn.Close()



在 Cmm.ExecuteNonQuery() ' 在这里执行半天也没做完！！！！！ 为什么？？

[hamadou]

使用TRY CATCH看下报什么错！
似乎你的SQL语句本身就有问题！

[wangchong]

错误是：当分配给命令的连接处于挂起的本地事务中时，命令必须具有事务对象才能执行。该命令的 Transaction 属性尚未初始化。

请帮忙

[huangjianyou]

只是执行一个语句，不加事务行不？

^_^

[mathsword]

先看数据库是否连上，然后看sql语句是否正确

[mathsword]

只执行一个语句没必要用事务，而且你又不用撤销操作。

例子
[Visual Basic]
Public Sub RunOracleTransaction(myConnString As String)
Dim myConnection As New OracleConnection(myConnString)
myConnection.Open()

Dim myCommand As OracleCommand = myConnection.CreateCommand()
Dim myTrans As OracleTransaction

' Start a local transaction
myTrans = myConnection.BeginTransaction(IsolationLevel.ReadCommitted)
' Assign transaction object for a pending local transaction

Try
myCommand.CommandText = "INSERT INTO Dept (DeptNo, Dname, Loc) values (50, 'TECHNOLOGY', 'DENVER')"
myCommand.ExecuteNonQuery()
myCommand.CommandText = "INSERT INTO Dept (DeptNo, Dname, Loc) values (60, 'ENGINEERING', 'KANSAS CITY')"
myCommand.ExecuteNonQuery()
myTrans.Commit()
Console.WriteLine("Both records are written to database.")
Catch e As Exception
myTrans.Rollback()
Console.WriteLine(e.ToString())
Console.WriteLine("Neither record was written to database.")
Finally
myConnection.Close()
End Try
End Sub


你的错误是：
Cmm.Transaction=tx

[mathsword]

就是你的事务没与OdbcCommand关联起来

odbc的例子

Public Sub RunOdbcTransaction(myConnString As String)
Dim myConnection As New OdbcConnection(myConnString)
myConnection.Open()

Dim myCommand As OdbcCommand = myConnection.CreateCommand()
Dim myTrans As OdbcTransaction

' Start a local transaction
myTrans = myConnection.BeginTransaction(IsolationLevel.ReadCommitted)
' Assign transaction object for a pending local transaction
myCommand.Transaction = myTrans

Try
myCommand.CommandText = "Insert into Region (RegionID, RegionDescription) VALUES (100, 'Description')"
myCommand.ExecuteNonQuery()
myCommand.CommandText = "Insert into Region (RegionID, RegionDescription) VALUES (101, 'Description')"
myCommand.ExecuteNonQuery()
myTrans.Commit()
Console.WriteLine("Both records are written to database.")
Catch e As Exception
Try
myTrans.Rollback()
Catch ex As OdbcException
If Not myTrans.Connection Is Nothing Then
Console.WriteLine("An exception of type " & ex.GetType().ToString() & _
" was encountered while attempting to roll back the transaction.")
End If
End Try

Console.WriteLine("An exception of type " & e.GetType().ToString() & _
"was encountered while inserting the data.")
Console.WriteLine("Neither record was written to database.")
Finally
myConnection.Close()
End Try
End Sub

[wangchong]

是的，我没有加：Cmm.Transaction = tx

[huangjianyou]

Cmm.CommandType = CommandType.Text

不要这句试试。

^_^

[huangjianyou]

Dim Cn As New SqlConnection
Dim Cm As New SqlCommand
Cn.ConnectionString = 连接串
Cn.Open()
Cm.Connection = Cn
Cm.CommandText = SQL语句
Cm.ExecuteNonQuery()
Cn.Close()
Cm = Nothing
Cn = Nothing

上面的是一个成功的例子。

你主要是检查你的数据库是否连接成功。

^_^