Does MWB 9.0.2.1.7 migrate LOBs correctly???

Question

Hi all,
just one question: will the new MWB migrate LOBs columns correctly? Our current version doesn�t (that�s a bug, told me by one of the developers) and after migrating all the tables from the source DB, we still have to use a Java program after that to connect to the source and target DB, make a join between the original and migrated tables, and open two streams to get and copy the LOB column... you get the picture.
If only MWB could do this in this new version , it would be a HUGE time saver for us...
Waiting for the answer (with great hope) ;-)
Luis Derani
DBA - Sysadmin
ALESP - SP
Brazil

Answer 1

Hello,
Unfortunately the problems regarding the migration of LOBS has not been resolved in the 92017 release. If you migrate using the OMWB, the LOBS may be migrated in the wrong order.
In order to migrate offline (using SQL*Loader), we folow a process whereby:
1. We migrate the database schema using the OMWB and we change the mapping of the LOB in question to a CLOB field in Oracle.
2. We then generate SQL*Loader scripts and BCP extraction scripts using the OMWB.
3. We then extract the data from the source database into data files.
4. Now, we use the generated SQL*Loader scripts to load the data into the tables in Oracle.
5. We then create a new BLOB field in the target Oracle database table - this will be used to store the correct LOB value when it is generated from the extracted CLOB field.
6. Next we use an inhouse PL/SQL procedure to convert the CLOB back to a BLOB - this is done in small pieces (50 hex pairs).
7. Finally, we remove the CLOB column.
This offline process reads worse than it actually is to implement! I have provided a piece of the conversion script that contains the inhouse PL/SQL procedure to convert a CLOB to a BLOB below. If you would like me to forward you the entire set of scripts, please let me know.
I hope this helps,
Tom.
CREATE OR REPLACE PROCEDURE CLOBTOBLOB
AS
inputLength      NUMBER;          -- size of input CLOB
offSet          NUMBER := 1;
pieceMaxSize     NUMBER := 50;      -- the max size of each peice
piece           VARCHAR2(50);      -- these pieces will make up the entire CLOB
currentPlace      NUMBER := 1;     -- this is where were up to in the CLOB
blobLoc          BLOB;               -- blob locator in the table
clobLoc           CLOB;               -- clob locator pointsthis is the value from the dat file
-- THIS HAS TO BE CHANGED FOR SPECIFIC CUSTOMER TABLE AND COLUMN NAMES
CURSOR cur IS SELECT filebinary_clob clob_column , filebinary blob_column FROM /*table*/tblFiles FOR UPDATE;
cur_rec cur%ROWTYPE;
BEGIN
          OPEN cur;
          FETCH cur INTO cur_rec;
          WHILE cur%FOUND
          LOOP
               --RETRIVE THE clobLoc and blobLoc
               clobLoc := cur_rec.clob_column;
               blobLoc := cur_rec.blob_column;
          currentPlace := 1; -- reset evertime
               -- find the lenght of the clob
               inputLength := DBMS_LOB.getLength(clobLoc);
          -- loop through each peice
               LOOP
                    -- get the next piece and add it to the clob
               piece := DBMS_LOB.subStr(clobLoc,pieceMaxSize,currentPlace);
                    -- append this peice to the BLOB
                    DBMS_LOB.WRITEAPPEND(blobLoc, LENGTH(piece)/2, HEXTORAW(piece));
          currentPlace := currentPlace + pieceMaxSize ;
     EXIT WHEN inputLength < currentplace;
     END LOOP;
     FETCH cur INTO cur_rec;
     END LOOP;
END CLOBtoBLOB;