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OracleDataReader Class

Provides a way of reading a forward-only stream of data rows from a data source. This class cannot be inherited.

Namespace: System.Data.OracleClient
Assembly: System.Data.OracleClient (in system.data.oracleclient.dll)

public sealed class OracleDataReader : DbDataReader
public final class OracleDataReader extends DbDataReader
public final class OracleDataReader extends DbDataReader

To create an OracleDataReader, you must call the ExecuteReader method of the OracleCommand object, rather than directly using a constructor.

Changes made to a resultset by another process or thread while data is being read may be visible to the user of the OracleDataReader.

IsClosed and RecordsAffected are the only properties that you can call after the OracleDataReader is closed. In some cases, you must call Close before you can call RecordsAffected.

More than one OracleDataReader can be open at any given time.

The following two Visual Basic examples demonstrate how to use an OracleDataReader to retrieve an Oracle REF CURSOR. These examples use tables that are defined in the Oracle Scott/Tiger schema, and require the following PL/SQL package and package body. You must create these on your server to use the examples.

Create the following Oracle package on the Oracle server.

CREATE OR REPLACE PACKAGE CURSPKG AS 
   TYPE T_CURSOR IS REF CURSOR; 
   PROCEDURE OPEN_ONE_CURSOR (N_EMPNO IN NUMBER, 
      IO_CURSOR IN OUT T_CURSOR); 
   PROCEDURE OPEN_TWO_CURSORS (EMPCURSOR OUT T_CURSOR, 
      DEPTCURSOR OUT T_CURSOR);
END CURSPKG;
/

Create the following Oracle package body on the Oracle server.


CREATE OR REPLACE PACKAGE BODY CURSPKG AS 
    PROCEDURE OPEN_ONE_CURSOR (N_EMPNO IN NUMBER, 
                               IO_CURSOR OUT T_CURSOR) 
    IS 
        V_CURSOR T_CURSOR; 
    BEGIN 
        IF N_EMPNO <> 0 THEN 
             OPEN V_CURSOR FOR 
             SELECT EMP.EMPNO, EMP.ENAME, DEPT.DEPTNO, DEPT.DNAME 
                  FROM EMP, DEPT 
                  WHERE EMP.DEPTNO = DEPT.DEPTNO 
                        AND EMP.EMPNO = N_EMPNO; 
        ELSE 
             OPEN V_CURSOR FOR 
             SELECT EMP.EMPNO, EMP.ENAME, DEPT.DEPTNO, DEPT.DNAME 
                  FROM EMP, DEPT 
                  WHERE EMP.DEPTNO = DEPT.DEPTNO; 
        END IF; 
        IO_CURSOR := V_CURSOR; 
    END OPEN_ONE_CURSOR; 
    PROCEDURE OPEN_TWO_CURSORS (EMPCURSOR OUT T_CURSOR, 
                                DEPTCURSOR OUT T_CURSOR) 
    IS 
        V_CURSOR1 T_CURSOR; 
        V_CURSOR2 T_CURSOR; 
    BEGIN 
        OPEN V_CURSOR1 FOR SELECT * FROM EMP; 
        OPEN V_CURSOR2 FOR SELECT * FROM DEPT; 
        EMPCURSOR  := V_CURSOR1; 
        DEPTCURSOR := V_CURSOR2; 
    END OPEN_TWO_CURSORS; 
END CURSPKG;
/

This Visual Basic example executes a PL/SQL stored procedure that returns a REF CURSOR parameter, and reads the value as an OracleDataReader.

Private Sub ReadOracleData(ByVal connectionString As String)
   Dim connection As New OracleConnection(connectionString)
   Dim command As New OracleCommand()
   Dim reader As OracleDataReader

   connection.Open()
   command.Connection = connection
   command.CommandText = "CURSPKG.OPEN_ONE_CURSOR"
   command.CommandType = CommandType.StoredProcedure
   command.Parameters.Add(New OracleParameter("N_EMPNO", OracleType.Number)).Value = 7369
   command.Parameters.Add(New OracleParameter("IO_CURSOR", OracleType.Cursor)).Direction = ParameterDirection.Output

   reader = command.ExecuteReader()
   While (reader.Read())
      ' Do something with the values.
   End While
   reader.Close()
   connection.Close()
End Sub

This Visual Basic example executes a PL/SQL stored procedure that returns two REF CURSOR parameters, and reads the values using an OracleDataReader.

Private Sub ReadOracleData(ByVal connectionString As String)
   Dim dataSet As New DataSet()
   Dim connection As New OracleConnection(connectionString)
   Dim command As New OracleCommand()
   Dim reader As OracleDataReader

   connection.Open()
   command.Connection = connection
   command.CommandText = "CURSPKG.OPEN_TWO_CURSORS"
   command.CommandType = CommandType.StoredProcedure
   command.Parameters.Add(New OracleParameter("EMPCURSOR", OracleType.Cursor)).Direction = ParameterDirection.Output
   command.Parameters.Add(New OracleParameter("DEPTCURSOR", OracleType.Cursor)).Direction = ParameterDirection.Output

   reader = command.ExecuteReader(CommandBehavior.CloseConnection)
   While (reader.Read())
      ' Do something with the values.
   End While
   reader.NextResult()
   While (reader.Read())
        ' Do something with the values.
   End While
   reader.Close()
   connection.Close()
 End Sub

This C# example creates an Oracle table and loads it with data. You must run this example prior to running the subsequent example, which demonstrates using an OracleDataReader to access the data using OracleType structures.

public void Setup(string connectionString)
{
   OracleConnection connection = new OracleConnection(connectionString);
   try
   {
      connection.Open();
      OracleCommand command = connection.CreateCommand();
      command.CommandText ="CREATE TABLE OracleTypesTable (MyVarchar2 varchar2(3000),MyNumber number(28,4) PRIMARY KEY,MyDate date, MyRaw raw(255))";
      command.ExecuteNonQuery();
      command.CommandText ="INSERT INTO OracleTypesTable VALUES ('test', 2, to_date('2000-01-11 12:54:01','yyyy-mm-dd hh24:mi:ss'), '0001020304')";
      command.ExecuteNonQuery();
      command.CommandText="SELECT * FROM OracleTypesTable";
   
   catch(Exception)
   {
   
   finally
   {
      connection.Close();
   

This C# example uses an OracleDataReader to access data, and uses several OracleType structures to display the data.

public void ReadOracleTypesExample(string connectionString)
{
   OracleConnection connection = new OracleConnection(connectionString);
   connection.Open();
   OracleCommand command = connection.CreateCommand();
   try
   {
      command.CommandText = "SELECT * FROM OracleTypesTable";
      OracleDataReader reader = command.ExecuteReader();
      reader.Read();
      //Using the Oracle specific getters for each type is faster than
      //using GetOracleValue.
      //First column, MyVarchar2, is a VARCHAR2 data type in Oracle Server
      //and maps to OracleString.
      OracleString oraclestring1 = reader.GetOracleString(0);
      Console.WriteLine("OracleString " + oraclestring1.ToString());

      //Second column, MyNumber, is a NUMBER data type in Oracle Server
      //and maps to OracleNumber.
      OracleNumber oraclenumber1 = reader.GetOracleNumber(1);
      Console.WriteLine("OracleNumber " + oraclenumber1.ToString());

      //Third column, MyDate, is a DATA data type in Oracle Server
      //and maps to OracleDateTime.
      OracleDateTime oracledatetime1 = reader.GetOracleDateTime(2);
      Console.WriteLine("OracleDateTime " + oracledatetime1.ToString());

      //Fourth column, MyRaw, is a RAW data type in Oracle Server and
      //maps to OracleBinary.
      OracleBinary oraclebinary1 = reader.GetOracleBinary(3);

      //Calling value on a null OracleBinary throws
      //OracleNullValueException; therefore, check for a null value.
      if (oraclebinary1.IsNull==false)
      {
         foreach(byte b in oraclebinary1.Value)
         {
            Console.WriteLine("byte " + b.ToString());
         
      
      reader.Close();
   
   catch(Exception e)
   {
      Console.WriteLine(e.ToString());
   
   finally
   {
      connection.Close();
   

The following example creates an OracleConnection, an OracleCommand, and an OracleDataReader. The example reads through the data, writing it out to the console. Finally, the example closes the OracleDataReader, then the OracleConnection.

public void ReadData(string connectionString)
{
    string queryString = "SELECT EmpNo, EName FROM Emp";
    using (OracleConnection connection = new OracleConnection(connectionString))
    {
        OracleCommand command = new OracleCommand(queryString, connection);
        connection.Open();
        OracleDataReader reader;
        reader = command.ExecuteReader();
        // Always call Read before accessing data.
        while (reader.Read())
        {
            Console.WriteLine(reader.GetInt32(0) + ", " + reader.GetString(1));
        
        // always call Close when done reading.
        reader.Close();
    


System.Object
   System.MarshalByRefObject
     System.Data.Common.DbDataReader
      System.Data.OracleClient.OracleDataReader

Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.

Windows 98, Windows 2000 SP4, Windows Millennium Edition, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see System Requirements.

.NET Framework

Supported in: 2.0, 1.1

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