Question

below is the code i am using for MySqlTransaction and it is running perfectly….
but problem is as i am using single instance of mysqlcommand i have to use unique PARAMETER in it. which is ruining my query. is there any other way around to do….

i tried to dispose cmd after each query but of no use.. 🙁

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          con.Open()
            Dim sqlTran As MySqlTransaction = con.BeginTransaction()
            Dim cmd As MySqlCommand = con.CreateCommand()
            cmd.Transaction = sqlTran
            Dim str As String = Nothing
            Try
                cmd.CommandText = "SELECT myid FROM memaster where    Adate=@adate and ANo=@ano and ASource=@asrc"
                cmd.Parameters.AddWithValue("@adate", txt_bpass_adate.Text)
                cmd.Parameters.AddWithValue("@ano", txt_bpass_af.Text)
                cmd.Parameters.AddWithValue("@asrc", txt_bpass_asource.Text)
                str = cmd.ExecuteScalar()
                'cmd.Dispose()'
                If str Is Nothing Then

                    cmd.CommandText = "Insert into memaster (ADate,ANo,ASource) values (@aDate,@aNo,@aSRC)"
                    cmd.Parameters.AddWithValue("@aDate", txt_bpass_adate.Text)
                    cmd.Parameters.AddWithValue("@aNo", txt_bpass_af.Text)
                    cmd.Parameters.AddWithValue("@aSRC", txt_bpass_asource.Text)

     cmd.ExecuteNonQuery()
    End If
     sqlTran.Commit()

            Catch ex As Exception
                Try
                    sqlTran.Rollback()
                Catch ex1 As Exception

                End Try
            End Try

---

i actually want to fire more then 4 queries in single transaction so that if anything go wrong i can rollback it…

if any onebody have any other method of it kindly share the concept wid me…

---

     For index As Integer = 1 To 5
                    cmd.CommandText = "Insert into detail (ID,BNos,SNo) values (@FID1,@BNo,@SeqN1)"
                    cmd.Parameters.AddWithValue("@FID1", str)
                    cmd.Parameters.AddWithValue("@BNo", str1)
                    cmd.Parameters.AddWithValue("@SeqN1", txt_bpass_sqn1.Text)
                    cmd.ExecuteNonQuery()


                Next

Answer 1

To execute multiple commands within the same transaction, ensure that you assign the transaction object to each command individually:

Dim selectCmd As MySqlCommand = con.CreateCommand()
Dim insertCmd As MySqlCommand = con.CreateCommand()

selectCmd.CommandText = "SELECT ..."
insertCmd.CommandText = "INSERT ..."

Dim sqlTran As MySqlTransaction = con.BeginTransaction()
Try
  selectCmd.Transaction = sqlTran
  insertCmd.Transaction = sqlTran

  ...selectCmd.ExecuteScalar()...
  ...insertCmd.ExecuteNonQuery()...

  sqlTran.Commit()
Catch
  sqlTran.Rollback()
End Try

As others have mentioned, it is generally a good idea to Dispose() objects (that are IDisposable) as soon as you’re done working with them. After disposing objects, they can no longer be used.