ExecuteScalar returns System.Decimal or System.Double on diff Oracle srvrs

Question

Hi,
Oracle Data Provider for .NET Developer's Guide states that Oracle type NUMBER maps to .NET type System.Decimal.
In my application I would like to retrieve value from database using simple query and OracleCommand.ExecuteScalar method. The problem is that on one database ExecuteScalar returns a value of type System.Decimal and on the other a value of type System.Double. Table creation script and C# code are shown below.
Since I declared column as NUMBER without any precision or scale, I wonder if there is a setting that specifies default values on Oracle server? If I declare column as NUMBER(38) I get the same result (System.Decimal) on both databases. But I would not like to change table creation scripts.
Oracle.DataAccess.dll (9.2.0.2102)
Database 1 (returns System.Decimal)
Oracle9i Enterprise Edition Release 9.2.0.2.0 - Production
PL/SQL Release 9.2.0.2.0 - Production
CORE     9.2.0.2.0     Production
TNS for Compaq Tru64 UNIX: Version 9.2.0.2.0 - Production
NLSRTL Version 9.2.0.2.0 � Production
Database 2 (returns System.Double)
Oracle9i Enterprise Edition Release 9.2.0.4.0 - Production
PL/SQL Release 9.2.0.4.0 - Production
CORE     9.2.0.3.0     Production
TNS for Compaq Tru64 UNIX: Version 9.2.0.4.0 - Production
NLSRTL Version 9.2.0.4.0 - Production
Database scripts:
CREATE TABLE TEST_TABLE (ID NUMBER NOT NULL) LOGGING NOCACHE NOPARALLEL;
ALTER TABLE TEST_TABLE ADD (CONSTRAINT PK_TEST_TABLE PRIMARY KEY (ID));
INSERT INTO TEST_TABLE ( ID ) VALUES (1);
COMMIT;
C# code:
using System;
using System.Data;
using Oracle.DataAccess.Client;
namespace TestOracle
     class MainRun
          [STAThread]
          static void Main(string[] args)
               if (args.Length != 1)
                    Console.WriteLine("usage: TestOracle.exe DSN");
                    return;
               string dsn = args[0];
               OracleConnection connection = null;
               OracleCommand cmd = null;
               try
                    connection = new OracleConnection(dsn);
                    connection.Open();
                    cmd = new OracleCommand();
                    cmd.CommandText = "SELECT ID FROM TEST_TABLE";
                    cmd.CommandType = CommandType.Text;
                    cmd.Connection = connection;
                    object retVal = cmd.ExecuteScalar();
                    Console.WriteLine(retVal.GetType().FullName);
                    connection.Close();
               finally
                    if (cmd != null)
                         cmd.Dispose();
                    if (connection != null)
                         connection.Dispose();

Answer 1

There was a fix on the database side that caused this behavior change but this was by design and intended. An event was also introduced as part of this fix so that this fix could be enabled or disabled on the database side. Please refer to the doc for more information.
ODP.NET has worked around this behavior change in ODP.NET itself so that the behavior is consistent between different database versions. Next release of ODP.NET would have this work around.