Re: Convert LONG (not RAW) to BLOB?
- From: "Tim Arnold" <timkarnold@xxxxxxxxxxx>
- Date: Wed, 30 Jul 2008 23:44:08 -0400
"Spiggy Topes" <ubik@xxxxxxx> wrote in message
news:6b9a4b00-6352-4812-a9f1-0c392af84dc0@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
I have an Oracle database containing several tables with LONGs - not
LONG RAW, just LONG. These tables were accessed by a VB application
using ADO and Microsoft's MSDATASHAPE provider. It's been perfectly
happily socking away and retrieving binary data to/from those LONGs
for several years now - archived Word documents, Outlook message files
and so forth.
Recently, I found out what happens when language settings at the
server and the desktop are different; character translation eats all
the binary data leaving useless mush.
So it behooves me to replace all the LONGs with BLOBs, before disaster
strikes.
Trouble is, I can't find a way of converting that doesn't require
reading each record using MSDATASHAPE as a LONG and writing it using
ORAOLEDB as a BLOB - the MS provider doesn't do BLOBs. All the simple
SQL suggestions I've found so far don't work, as they either won't
allow for conversion of a field defined as LONG to any binary format,
or as soon as they hit non-character data they die.
Anyone have a workable method to get around this?
Metalink Note:1012454.7
he following example shows an alternate method for converting LONG
columns into BLOBs using PL/SQL.
REM long2lob.sql
REM Version 1.0, last updated 8/8/97
REM This procedure copies LONG data into a CLOB, as described in
REM Chapter 21 of _Oracle8 PL/SQL Programming_ by Scott Urman.
CREATE OR REPLACE PROCEDURE Long2Lob(
-- Uses DBMS_SQL to select a LONG column identified by p_LongQuery, and
-- returns it in p_CLob.
p_LongQuery IN VARCHAR2,
p_CLob IN OUT CLOB) AS
c_ChunkSize CONSTANT INTEGER := 100;
v_CursorID INTEGER;
v_RC INTEGER;
v_Chunk VARCHAR2(100);
v_ChunkLength INTEGER;
v_Offset INTEGER := 0;
BEGIN
-- Open the cursor, define, execute, and fetch.
v_CursorID := DBMS_SQL.OPEN_CURSOR;
DBMS_SQL.PARSE(v_CursorID, p_LongQuery, DBMS_SQL.V7);
DBMS_SQL.DEFINE_COLUMN_LONG(v_CursorID, 1);
v_RC := DBMS_SQL.EXECUTE_AND_FETCH(v_CursorID);
-- Loop over the LONG, fetching c_ChunkSize characters at a time from
-- the LONG and adding them to the LOB.
LOOP
DBMS_SQL.COLUMN_VALUE_LONG(v_CursorID, 1, c_ChunkSize, v_Offset,
v_Chunk, v_ChunkLength);
DBMS_LOB.WRITE(p_CLob, v_ChunkLength, v_Offset + 1, v_Chunk);
IF v_ChunkLength < c_ChunkSize THEN
EXIT;
ELSE
v_Offset := v_Offset + v_ChunkLength;
END IF;
END LOOP;
DBMS_SQL.CLOSE_CURSOR(v_CursorID);
EXCEPTION
WHEN OTHERS THEN
-- Clean up, and reraise the error.
DBMS_SQL.CLOSE_CURSOR(v_CursorID);
RAISE;
END Long2Lob;
/
.
- References:
- Convert LONG (not RAW) to BLOB?
- From: Spiggy Topes
- Convert LONG (not RAW) to BLOB?
- Prev by Date: Re: Oracle snapshots don't always do what I want
- Next by Date: Q: detect uncommited changes
- Previous by thread: Convert LONG (not RAW) to BLOB?
- Next by thread: Q: detect uncommited changes
- Index(es):
Relevant Pages
|
Loading
