Read

Overrides Stream

This instance method reads a specified amount of bytes from the OracleBFile instance and populates the buffer.

Declaration

// C#
public override int Read(byte[] buffer, int offset, int count);

Parameters

buffer

The byte array buffer to be populated.
offset

The offset of the byte array buffer to be populated.
count

The amount of bytes to read.

Return Value

The return value indicates the number of bytes read from the BFILE, that is, the external LOB.

Exceptions

ObjectDisposedException - The object is already disposed.

InvalidOperationException - The OracleConnection is not open or has been closed during the lifetime of the object.

ArgumentOutOfRangeException - Either the offset or the count parameter is less than 0 or the offset is greater than or equal to the buffer.Length or the offset and the count together are greater than buffer.Length.

Remarks

The LOB data is read starting from the position specified by the Position property.

Example

// Database Setup, if you have not done so yet.
/* Log on as DBA (SYS or SYSTEM) that has CREATE ANY DIRECTORY privilege.
 
CREATE OR REPLACE DIRECTORY MYDIR AS 'C:\TEMP';
 
*/
 
// C#
 
using System;
using Oracle.DataAccess.Client;
using Oracle.DataAccess.Types;
 
class ReadSample
{
  static void Main()
  {
    // Create MYDIR directory object as indicated previously and create a file
    // MyFile.txt with the text ABCDABC under C:\TEMP directory.
    // Note that the byte representation of the ABCDABC is 65666768656667
 
    string constr = "User Id=scott;Password=tiger;Data Source=oracle";
    OracleConnection con = new OracleConnection(constr);
    con.Open();
 
    OracleBFile bFile = new OracleBFile(con, "MYDIR", "MyFile.txt");
 
    // Open the OracleBFile
    bFile.OpenFile();
 
    // Read 7 bytes into readBuffer, starting at buffer offset 0
    byte[] readBuffer = new byte[7];       
    int bytesRead = bFile.Read(readBuffer, 0, 7);
    
    // Prints "bytesRead  = 7"
    Console.WriteLine("bytesRead  = " + bytesRead);    
 
    // Prints "readBuffer = 65666768656667"
    Console.Write("readBuffer = ");
    for(int index = 0; index <  readBuffer.Length; index++)
    {
      Console.Write(readBuffer[index]);
    }
    Console.WriteLine();
 
    // Close the OracleBFile
    bFile.CloseFile();
 
    bFile.Close();
    bFile.Dispose();
 
    con.Close();
    con.Dispose();
  }
}