JDBC for Oracle - Herong's Tutorial Examples - v3.13, by Herong Yang
Inserting BLOB Values with setBlob() Method
This section describes how to insert BLOB values with the PreparedStatement.setBlob() method.
If you want to insert a BLOB column with a character string that comes from a java.sql.Blob object, you can directly set the value with PreparedStatement.setBlob() method.
To test this, I wrote the following program to copy some records with BLOB values as new records back into the same table. During the copy process, the BLOB values are also modified with some Blob object methods - The first 6 bytes are replaced with 0 values.
/* OracleBlobSetBlob.java * Copyright (c) HerongYang.com. All Rights Reserved. */ import java.io.*; import java.sql.*; public class OracleBlobSetBlob { public static void main(String [] args) { Connection con = null; try { oracle.jdbc.pool.OracleDataSource ds = new oracle.jdbc.pool.OracleDataSource(); ds.setDriverType("thin"); ds.setServerName("localhost"); ds.setPortNumber(1521); ds.setDatabaseName("XE"); ds.setUser("Herong"); ds.setPassword("TopSecret"); con = ds.getConnection(); // Deleting records for re-testing Statement sta = con.createStatement(); sta.executeUpdate( "DELETE FROM Image WHERE Subject LIKE 'Copy of %'"); // Creating a PreparedStatement for inserting new records PreparedStatement ps = con.prepareStatement( "INSERT INTO Image (Subject, Body, ID) VALUES (?,?,?)"); // Looping though the first 3 records ResultSet res = sta.executeQuery( "SELECT * FROM Image ORDER BY ID"); int i = 0; while (res.next() && i<3) { i++; System.out.println("Copying record ID: "+res.getInt("ID")); String subject = res.getString("Subject"); Blob body = res.getBlob("Body"); // Modifying the Blob object byte[] chuck = {(byte)0x00, (byte)0x00, (byte)0x00, (byte)0x00, (byte)0x00, (byte)0x00}; body.setBytes(1,chuck); // Inserting a new record with setBlob() ps.setString(1, "Copy of "+subject); ps.setBlob(2,body); ps.setInt(3,res.getInt("ID")); ps.executeUpdate(); } ps.close(); res.close(); // Checking the new records res = sta.executeQuery( "SELECT * FROM Image WHERE Subject LIKE 'Copy of %'"); while (res.next()) { System.out.println("Record ID: "+res.getInt("ID")); System.out.println(" Subject = "+res.getString("Subject")); byte[] body = res.getBytes("Body"); String bodyHex = bytesToHex(body, 32); System.out.println(" Body in HEX = "+bodyHex+"..."); } res.close(); sta.close(); con.close(); } catch (Exception e) { e.printStackTrace(); } } public static String bytesToHex(byte[] bytes, int max) { StringBuffer buffer = new StringBuffer(); for (int i=0; i<bytes.length && i<max; i++) { buffer.append(Integer.toHexString(bytes[i] & 0xFF)); } return buffer.toString().toUpperCase(); } }
Unfortunately, my program failed because Oracle JDBC driver requires that the result set row must be locked:
herong> java -cp .;ojdbc11.jar OracleBlobSetBlob Copying record ID: 1 java.sql.SQLException: ORA-22920: row containing the LOB value is not locked at oracle.jdbc.driver.DatabaseError.throwSqlException( DatabaseError.java:112) at oracle.jdbc.driver.T4CTTIoer.processError(T4CTTIoer.java:331) at oracle.jdbc.driver.T4CTTIoer.processError(T4CTTIoer.java:283) at oracle.jdbc.driver.T4CTTIoer.processError(T4CTTIoer.java:278) at oracle.jdbc.driver.T4C8TTILob.receiveReply(T4C8TTILob.java:930) at oracle.jdbc.driver.T4C8TTILob.write(T4C8TTILob.java:249) at oracle.jdbc.driver.T4CConnection.putBytes( T4CConnection.java:1971) at oracle.sql.BLOB.setBytes(BLOB.java:725) at OracleBlobSetBlob.main(OracleBlobSetBlob.java:43)
The problem is caused by the Oracle JDBC driver implementation of ResultSet objects. The Blob object returned by getBlob() is still tied up to the ResultSet object. When Blob object is updated, Oracle consider that the ResultSet is updated, which requires locking the row in the database for automatic updates.
In another word, Oracle does not allow you to update result set. If you do, Oracle will try to persist the changes back to the database.
Table of Contents
JDBC (Java Database Connectivity) Introduction
Oracle Express Edition Installation on Windows
Oracle - Reference Implementation of JdbcRowSet
Oracle - JBDC CallableStatement
Oracle CLOB (Character Large Object) - TEXT
►Oracle BLOB (Binary Large Object) - BLOB
Overview of BLOB (Binary Large Object)
Create Tables with CLOB Columns
Inserting BLOB Values with SQL INSERT Statements
Inserting BLOB Values with setBytes() Method
Inserting BLOB Values with setBinaryStream() Method
Closing InputStream Too Early on setBinaryStream()
Retrieving BLOB Values with getBytes() Method
Retrieving BLOB Values with getBinaryStream() Method
Retrieving BLOB Values with getBlob() Method
►Inserting BLOB Values with setBlob() Method
Copying BLOB Values to New Rows