如何使用C＃从Oracle数据库检索大数据？

Question

I am trying to retrieve a large amount of data from an Oracle database in .NET. I am using a .NET DBDataReader which is working fine with small amount of data but when the data become medium or large it stops functioning and I have no idea why. How can i retrieve large amount of data?

Answer 1

You should try using ODP.NET . That is Oracle Data Provider written for .NET and it's much better optimized for communication with Oracle databases.

Microsoft deprecated Oracle Client (System.Data.OracleClient) ( http://blogs.msdn.com/adonet/archive/2009/06/15/system-data-oracleclient-update.aspx ) and advised to use 3rd hand tools.

EDITED:

Maby you should take a look at this similar question and answer: Big Performance Problems With Oracle DataReader in .Net

Answer 2

Ok, since you are expecting answers related to your question with very little information, answering these would help OTHERS to answer your question:

1- What is your data type in database

2- How are you trying to fetch the data (Some code would help a lot)

3- Are there any indexes, how big is the table and how complex is your query, have you tried optimizing it? Try writing your query.

...

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Ok, here is what you can try and tell us if it changed anything...

static void DownloadBlob(OracleConnection myConnection)
{
  OracleCommand myCommand = new OracleCommand("SELECT * FROM table", myConnection);
  myConnection.Open();
  OracleDataReader myReader = myCommand.ExecuteReader(System.Data.CommandBehavior.Default);
  try
  {
    while (myReader.Read())
    {
      //Obtain OracleLob directly from OracleDataReader
      OracleLob myLob = myReader.GetOracleLob(myReader.GetOrdinal("Ordinal"));
      if (!myLob.IsNull)
      {
        // I hope it is BLOB :)
      }
    }
  }
  finally
  {
    myReader.Close();
    myConnection.Close();
  }
}