Select for update issue in oracle using ado.net

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Hi,
I have the following code part. I am reading a table data inside a transaction, then update it. While reading i need to put a lock (i dont want any other transaction access the same table even for read). I have used "for update" method inside the query, but it is not working: Nothing is coming, what is the problem with this code:

C#

try
    {
        myOracleConnection = gcnew OracleConnection("Data Source=(DESCRIPTION=(ADDRESS_LIST=(ADDRESS=(PROTOCOL=TCP)(HOST=1.1.1.1)(PORT=1521)))(CONNECT_DATA=(SERVER=DEDICATED)(SERVICE_NAME=SCDB)));User Id=user;Password=pw;");
        myOracleConnection->Open();
        myTransaction = myOracleConnection->BeginTransaction();
        myDataAdapter = gcnew OracleDataAdapter();
        selectionString = "select * from db.tablename FOR UPDATE";
        OracleCommand ^selectCommand = gcnew OracleCommand(selectionString);
        myDataAdapter->SelectCommand = selectCommand;
        myDataAdapter->SelectCommand->Transaction = myTransaction;
        myDataAdapter->SelectCommand->Connection = myOracleConnection;
        myDataAdapter->SelectCommand->ExecuteNonQuery();

        myDataSet = gcnew DataSet("sample");
        myDataAdapter->FillSchema(myDataSet,SchemaType::Source, "pele_misc");
        myDataAdapter->Fill (myDataSet,"pele_misc");
        dt = myDataSet->Tables["pele_misc"];
        myDataSet->WriteXml("G:/data10.xml");

        updateString = "update db.tablename set value = 'http://www.yahoo.co.in' where name like 'XEN_SUPPORT_URL'";
        OracleCommand ^updateCommand = gcnew OracleCommand(updateString);
        updateCommand->Connection = myOracleConnection;
        myDataAdapter->UpdateCommand = updateCommand;
        myDataAdapter->UpdateCommand->Transaction = myTransaction;
        myDataAdapter->UpdateCommand->ExecuteNonQuery();
        System::Threading::Thread::Sleep(20000);
        myTransaction->Commit();

    }
    catch(Exception ^ e)
    {
        myTransaction->Rollback();
        Console::Write(e->ToString () );
    }
    __finally
    {

        myOracleConnection->Close();
    }

Posted 2-Dec-14 22:55pm

Member 11168418

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Kornfeld Eliyahu Peter · Answer 1 · 2014-12-02T23:29:00

Solution 1

MSDN:
ExecuteNonQuery returns no rows

http://msdn.microsoft.com/en-us/library/system.data.sqlclient.sqlcommand.executenonquery%28v=vs.110%29.aspx[^]

I think you should use ExecuteReader...

Posted 2-Dec-14 23:29pm

Kornfeld Eliyahu Peter

Comments

Member 11168418 3-Dec-14 6:07am

Tried everything, ExecuteNonQuery, ExecuteReader, ExecuteOracleNonQuery etc. Got nothing in all cases. Any chance to have problem with connection, i am accessing db from a remote machine.

Kornfeld Eliyahu Peter 3-Dec-14 6:08am

I believe you should got an error in case of such problems...

Member 11168418 3-Dec-14 6:15am

Problem shows if i use the query like: select * from db.tablename FOR UPDATE
but query "select * from db.tablename" is working fine, but the update query wont be worked in this case too.