Opening a BFILE with FILEOPEN

Figure 12-13 Use Case Diagram: Opening a BFILE with FILEOPEN

Text description of the illustration adl12bf7.gif

See Also: "Use Case Model: External LOBs (BFILEs)" for all basic operations of External LOBs (BFILES).

Purpose

This procedure describes how to open a BFILE using FILEOPEN.

Usage Notes

While you can continue to use the older FILEOPEN form, we strongly recommend that you switch to using OPEN, because this facilitates future extensibility.

Syntax

See Chapter 3, "LOB Support in Different Programmatic Environments" for a list of available functions in each programmatic environment. Use the following syntax references for each programmatic environment:

• PL/SQL (DBMS_LOB) (Oracle9i Supplied PL/SQL Packages Reference): Chapter 18, "DBMS_LOB" -- FILEOPEN, FILECLOSE

• C (OCI) (Oracle Call Interface Programmer's Guide): Chapter 7, "LOB and File Operations, for usage notes. Chapter 15, "Relational Functions" -- LOB Functions, OCILobFileOpen, OCILobFileClose, OCILobFileSetName

• COBOL (Pro*COBOL): A syntax reference is not applicable in this release.

• C/C++ (Pro*C/C++): A syntax reference is not applicable in this release.

• Visual Basic (OO4O): A syntax reference is not applicable in this release.

• Java (JDBC) (Oracle9i JDBC Developer's Guide and Reference): Chapter 7, "Working With LOBs" -- Creating and Populating a BLOB or CLOB Column. Further extensions are available in ( Oracle9i SQLJ Developer's Guide and Reference): Chapter 5, "Type Support", Oracle Type Support, Support for BLOB, CLOB, and BFILE.

Scenario

These examples open a Lincoln_photo in operating system file PHOTO_DIR. Examples are provided in the following four programmatic environments:

Examples

• PL/SQL: Opening a BFILE with FILEOPEN

• C (OCI): Opening a BFILE with FILEOPEN

• COBOL (Pro*COBOL): No example is provided with this release.

• C/C++ (Pro*C/C++): No example is provided with this release.

• Visual Basic (OO4O): Opening a BFILE with FILEOPEN

• Java (JDBC): Opening a BFILE with FILEOPEN

PL/SQL: Opening a BFILE with FILEOPEN

/* Note that the example procedure openBFILE_procOne is not part of the 
   DBMS_LOB package: */
CREATE OR REPLACE PROCEDURE openBFILE_procOne IS 
   File_loc    BFILE := BFILENAME('PHOTO_DIR', 'Lincoln_photo'); 
BEGIN 
   /* Open the BFILE: */ 
   DBMS_LOB.FILEOPEN (File_loc, DBMS_LOB.FILE_READONLY);
   /* ... Do some processing. */ 
   DBMS_LOB.FILECLOSE(File_loc);
END; 

C (OCI): Opening a BFILE with FILEOPEN

void BfileOpen(envhp, errhp, svchp, stmthp)
OCIEnv  *envhp; 
OCIError *errhp; 
OCISvcCtx *svchp; 
OCIStmt *stmthp; 
{ 
     OCILobLocator *bfile_loc; 
 
     /* Allocate the locator descriptor */ 
     (void) OCIDescriptorAlloc((dvoid *) envhp, (dvoid **) &bfile_loc,  
                               (ub4) OCI_DTYPE_FILE,  
                               (size_t) 0, (dvoid **) 0);
     
     /* Set the bfile locator information */ 
     checkerr(errhp, (OCILobFileSetName(envhp, errhp, &bfile_loc,  
                                        (OraText *)"PHOTO_DIR", 
                                        (ub2)strlen("PHOTO_DIR"),  
                                        (OraText *)"Lincoln_photo",  
                                        (ub2)strlen("Lincoln_photo")))); 
  checkerr(errhp, OCILobFileOpen(svchp, errhp, bfile_loc, 
                                 (ub1)OCI_FILE_READONLY));
  /* ... Do some processing. */
  checkerr(errhp, OCILobFileClose(svchp, errhp, bfile_loc));

  /* Free the locator descriptor */ 
  OCIDescriptorFree((dvoid *)bfile_loc, (ub4)OCI_DTYPE_FILE); 
} 

Visual Basic (OO4O): Opening a BFILE with FILEOPEN

Note: At the present time, OO4O only offers BFILE opening with OPEN (see "Visual Basic (OO4O) Opening a BFILE with OPEN").

Java (JDBC): Opening a BFILE with FILEOPEN

import java.io.OutputStream;
// Core JDBC classes: 
import java.sql.DriverManager;
import java.sql.Connection;
import java.sql.Statement;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;

// Oracle Specific JDBC classes: 
import oracle.sql.*;
import oracle.jdbc.driver.*;

public class Ex4_38
{

  public static void main (String args [])
       throws Exception
  {
    // Load the Oracle JDBC driver: 
    DriverManager.registerDriver(new oracle.jdbc.driver.OracleDriver());

    // Connect to the database: 
    Connection conn =
      DriverManager.getConnection ("jdbc:oracle:oci8:@", "samp", "samp");

    conn.setAutoCommit (false);

    // Create a Statement: 
    Statement stmt = conn.createStatement ();
    try
    {
       BFILE src_lob = null;
       ResultSet rset = null;

       rset = stmt.executeQuery (
       "SELECT BFILENAME('PHOTO_DIR', 'Lincoln_photo') FROM DUAL");
       if (rset.next())
       {
           src_lob = ((OracleResultSet)rset).getBFILE (1);

           src_lob.openFile();
          System.out.println("The file is now open");
        }

        // Close the BFILE, statement and connection: 
        src_lob.closeFile();
        stmt.close();
        conn.commit();
        conn.close();
    }
    catch (SQLException e)
    {
        e.printStackTrace();
    }
  }
}