Why the data in the database changed

Question

the code is like this:
private boolean dbUpdate() throws SQLException, IOException {
Connection conn = null;
try {
conn = ConnectHandle.getDBConnection();
conn.setAutoCommit(false);
PreparedStatement pstUpdate =
conn.prepareStatement("UPDATE mytable SET ID= ?, NAME=?,CONTENT=null");
pstUpdate.setString(1, this.getID);
pstUpdate.setString(2, this.getName());
if (pstUpdate.executeUpdate() > 0 && dbUpdateContent(conn)) {
conn.commit();
return true;
else {
conn.rollback();
return false;
catch (SQLException e) {
conn.rollback();
throw e;
catch (IOException e) {
conn.rollback();
throw e;
finally {
if (conn != null) {
conn.setAutoCommit(true);
ConnectHandle.freeDBConnection(conn);
private boolean dbUpdateContent(Connection conn) throws
SQLException, java.io.IOException {
if (getContent() == null)
return true;
PreparedStatement pstUpdate = conn.prepareStatement(.
"UPDATE mytable SET CONTENT = empty_clob() WHERE ID = ?");
pstUpdate.setString(1, getId());
pstUpdate.executeUpdate();
PreparedStatement pstSelect = conn.prepareStatement(
"SELECT CONTENT FROM DOC_SENDED_ARCHIVE WHERE ID = ? FOR UPDATE");
pstSelect.setString(1, getId());
OracleResultSet ors = (OracleResultSet) pstSelect.executeQuery();
if (!ors.next())
return false;
CLOB clob = ( (OracleResultSet) ors).getCLOB(1);
Writer writer = clob.getCharacterOutputStream();
writer.write(getContent());
writer.close();
ors.close();
return true;
i want to insert and update records in oracle talbe,the table contains a clob field
but it sometimes (not always ) throws sqlexception ,
java.sql.SQLException: ORA-01002: fetch out of sequence     at oracle.jdbc.dbaccess.DBError.throwSqlException(DBError.java:134)
     at oracle.jdbc.ttc7.TTIoer.processError(TTIoer.java:289)
     at oracle.jdbc.ttc7.Oall7.receive(Oall7.java:573)
     at oracle.jdbc.ttc7.TTC7Protocol.doOall7(TTC7Protocol.java:1891)
     at oracle.jdbc.ttc7.TTC7Protocol.fetch(TTC7Protocol.java:1198)
     at oracle.jdbc.driver.OracleStatement.doExecuteQuery(OracleStatement.java:2400)
     at oracle.jdbc.driver.OracleStatement.doExecuteWithTimeout(OracleStatement.java:2672)
     at oracle.jdbc.driver.OraclePreparedStatement.executeUpdate(OraclePreparedStatement.java:589)
     at oracle.jdbc.driver.OraclePreparedStatement.executeQuery(OraclePreparedStatement.java:527)
     at com.abc.MyClass.dbUpdateContent(SendedArchive.java:457)
     at com.abc.MyClass.dbUpdate(SendedArchive.java:415)
why throw this exception?
and other question is
when throw this Exception ,it execute conn.rollback(),the database should not change,but in database
the name is changed,why?

Answer 1

I'm not sure if this solves your problem, but I think you need to do this:
// This is your original code
//conn.prepareStatement("UPDATE mytable SET ID= ?, NAME=?,CONTENT=null");
//pstUpdate.setString(1, this.getID);
//pstUpdate.setString(2, this.getName());
// This is what I'd recommend
conn.prepareStatement("UPDATE mytable SET ID= ?, NAME=?,CONTENT=?");
pstUpdate.setString(1, this.getID);
pstUpdate.setString(2, this.getName());
pstUpdate.setNull(3, java.sql.Types.VARCHAR);You want to set that CONTENT column to a SQL null, not a Java null. - MOD