Using Asynchronously in .C# to Oracle database

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Hi there,

I am currently working on a bespoke application that needs to extract the data from Oracle database table and preview it in a grid before the user click export to export it to text file.

The table contains huge transactional data and it takes long to return results.
There is nothing much I can do with the query as I have already optimized it.
I want the user to be able to perform some other work while waiting for the data to return or at least return data in batches.

I tried to use Asynchronously, but I am getting connection problem when using the following connection string:

conn = new OracleConnection("Data Source=111.00.000.11:port/SID;Persist Security Info=True;User ID=username;Password=pwd;  Asynchronous Processing=true");

I get: 'Asynchronous Processing' is an invalid connection string attribute'.

I also can't use BeginExecuteReader as it is not defined in OracleCommand.

Error 4

'Oracle.DataAccess.Client.OracleCommand' does not contain a definition for 'BeginExecuteReader' and no extension method 'BeginExecuteReader' accepting a first argument of type 'Oracle.DataAccess.Client.OracleCommand' could be found (are you missing a using directive or an assembly reference?)

Anyone will ideas how I can get around this or any advice regarding my overall possible solution around this.

Thank you in-advance for your prompt help.

Posted 31-Mar-11 5:27am

Obopeng

Updated 31-Mar-11 6:05am

Dalek Dave

v2

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Comments

[no name] 31-Mar-11 11:40am

What environment is this for, web or Windows?

Obopeng 1-Apr-11 4:08am

Hi Mark thank you for you contribution. It is a windows app.

Dylan Morley 31-Mar-11 11:51am

What version of .Net framework, do you have 4.0 and access to Tasks?

Obopeng 1-Apr-11 4:10am

I am using .Net 3.5 framework. Thank u for your contribution too.

Dalek Dave 31-Mar-11 12:06pm

Edited for Readability and Code Blocks.

2 solutions

Solution 1

Try this http://msdn.microsoft.com/en-us/library/bb746685(v=PandP.50).aspx[^]

Posted 31-Mar-11 5:42am

Not Active

Comments

Obopeng 1-Apr-11 4:22am

Tnx for all your inputs.

I tried to use examples from these links:
http://aspadvice.com/blogs/azamsharp/archive/2007/04/05/Executing-a-Query-Asynchronously-in-.NET-2.0.aspx

http://www.csharphelp.com/2007/07/asynchronous-data-access-using-callback-model/

The above links are similar thing that I want to do. There problem is that the examples are for SQL Server db and I am using Oracle db. I get an error when I try to use things like: "Asynchronous Processing=true" and BeginExecuteReader as shown in the database. Once again I highly appreciate all your contribution.

Thanks

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Dylan Morley · Accepted Answer · 2011-03-31T06:01:00

If you're on .Net 4.0, you can use Tasks and Continuations to wrap your data access. E.g.

C#

var context = TaskScheduler.FromCurrentSynchronizationContext();

var task = Task.Factory.StartNew(() =>
{
    DataTable data = SomeSortOfDatacontext.GetOrders();
    return data;
});

task.ContinueWith(data =>
{
    DataTable data = data.Result;
    foreach(Row row in data.Rows)
    {
        // blah blah blah
    }
},
System.Threading.CancellationToken.None,
TaskContinuationOptions.OnlyOnRanToCompletion, context);

The good thing about Tasks is that it automatically handles marshalling to the UI thread by providing a SynchronizationContext

Otherwise, you could just use the ThreadPool[^] or IAsyncResult[^]

Lots of options available to achieve this :)