How to concatinate two clob objects using JDBC...good brain excercise!!!

Question

Hi,
I am using MYSQL server ver. 4.0 and J/Connector version 3.0.6
I have two columns of LONGTEXT type and i have to concatenate them and store it in a third column.I have thought of the following strategy:
1. Retrieve the columns as CLOB using getClob()
2.Concatinate the CLOB values and then insert it in the corr. database column.
My problem is this that i don't know what strategy should i use to concatenate the two values in the clob objects without bringing the whole clob values in the memeory.If i use this strategy..it gives me outofmemory error.
My Clob columns may go upto 10MB in size.
Pl. help.....Any suggestions from the whizkids out there will be extremely appreciated!!!
Thanks....

Answer 1

sorry for replying so late...but neway....
Ok...i will paste a snapshot of my code here....May be that will clarify a few things....
I am opening this in the main function body....To get the first column cell value....
/////////////////Reading the Clob value of the main outer row which will be copmpared with the other rows under it//
BufferedInputStream anInputStream = new BufferedInputStream( rs.getAsciiStream("row_interaction")); //row_intrctn
int aByte = anInputStream.read();
File aFile = File.createTempFile( "tempfile", "txt");
FileOutputStream anOutput = new FileOutputStream(aFile);
while (aByte != -1)
anOutput.flush();
          anOutput.write(aByte);
aByte = anInputStream.read();
Then I depending on some condition i concatenate it with some other cell value from the database ...here i am just concatenating it with another rows column cell clob value..shown below as:
if(loop==0)
String col_string= null;
col_string= convert_bitset_string(temp_b);
//////Getting the other string value///////////////////////////////////////
anInputStream = new BufferedInputStream( rs.getAsciiStream("row_interaction"));
aByte = anInputStream.read();
while (aByte != -1)
anOutput.write(aByte);
aByte = anInputStream.read();
anOutput.flush();
System.out.println("Loop0,2:The "+row_index+"st row being inserted");
////////////////////////Inserting through the prepared statement////////////
String insertion= "Insert into bv"+next_tbl_nm_cntr+" Values(?,?,"+col_string+")";
PreparedStatement pstmt= con.prepareStatement(insertion);
pstmt.setInt(1,row_index);
try{
FileInputStream fis = new FileInputStream(aFile);
pstmt.setAsciiStream(2,fis,(int)aFile.length());
pstmt.execute();
fis.close();
}catch(IOException e)
System.out.println("Error in setting the stream"+e);
System.out.println("Loop0,2:Row inserted");
row_index++;
loop++;
}     //End if: loop=0 i.e the row being inserted is the first row
                              //in the store bitset
Tell me if there is any error because when it concatenates i get some unwanted values too..which i took before in the iteration.....
Any help will be greatly appreciated