Re: global temporary table --> invalid ROWID?

"Corrine" <JavaDeveloper_at_volcanomail.com> wrote in message news:54774824.0310031329.40c9b5df_at_posting.google.com...
> Is a temporary table really more expensive than a regular table?
> Actually, I prefer a temporary table, because my application serves
> multiple users simultaneously. I am concerned about concurrency
> issues that arise if I use
> just a regular table.
>
> Speaking of which, what if I use a temporary BLOB rather than a
> temporary table? I am trying to do this now, but I can't figure out
> how to get the modified BLOB object back to Java after the PLSQL block
> has finished executing.
>
> I do:
>
> BLOB bl = BLOB.createTemporary(db,true,BLOB.DURATION_SESSION);
> CallableStatement plsqlblock = conn.prepareCall(
> "declare\n"+
> " stuff... \n"+
> "begin\n"+
> " procThatModifiesBLOB(?);\n"+
> "end;\n");
> plsqlblock.setBlob(1, bl);
> plsqlblock.execute();
>
> bl = plsqlblock.getBlob(1); //**** doesn't work.
>
> How do I retrieve the modified value of "bl" after "plsqlblock"
> finishes executing?
>
>
> "Jim Kennedy" <kennedy-down_with_spammers_at_no_spam.comcast.net> wrote in
 message news:<Pxffb.485819$Oz4.329946_at_rwcrnsc54>...
>
> If it works on a regular table then why are you making things more
> expensive
> > by putting it in a temp table first? Just get it out of the regular
 table.
> > Jim
 

> > "Oracle_Technet" <oracle_technet_at_yahoo.com> wrote in message
> > news:c3e04899.0310022230.799c3a82_at_posting.google.com...
> > > Reason as per my understanding: java front end would be using
> > > connection pooling, and the session is not bound. so once the back end
> > > proc gives the output back to front end, and then the front end tries
> > > to access the blob stored in the global temp table, it will give
> > > error, as global temp table is session specific. (so rowid not found).
> > > Same type of errors would be encountered with ref cursors based on
> > > global temp tables.
> > > So, don't use Global Temporary tables for returning resultsets to java
> > > front end.
> > > Hope this helps.
> > >
> > > JavaDeveloper_at_volcanomail.com (Corrine) wrote in message
 news:<54774824.0309290654.58fb3f16_at_posting.google.com>...
> > > > Hi,
> > > >
> > > > I am creating a global temporary table that is session-specific. I
> > > > insert a BLOB into this table, and then select the BLOB from this
> > > > table into a ResultSet. The ResultSet sees this BLOB object, and I
 am
> > > > able to get the binary input stream from this blob. However, when I
> > > > invoke InputStream.read(byte[]) on this input stream, I get the
> > > > following exception:
> > > >
> > > > java.io.IOException: ORA-01410: invalid ROWID
> > > > ORA-06512: at "SYS.DBMS_LOB", line 751
> > > > ORA-06512: at line 1
> > > >
> > > >
> > > > at oracle.jdbc.dbaccess.DBError.SQLToIOException(DBError.java:625)
> > > >
> > > > at
> >

 oracle.jdbc.driver.OracleBlobInputStream.needBytes(OracleBlobInputStream.jav
> > a:179)
> > > >
> > > > at
> >

 oracle.jdbc.driver.OracleBufferedStream.read(OracleBufferedStream.java:113)
> > > >
> > > > at
> >

 oracle.jdbc.driver.OracleBufferedStream.read(OracleBufferedStream.java:91)
> > > > ...
> > > >
> > > > Just for clarity, here is basically the code I'm using:
> > > >
> > > > CallableStatement cstmt2 = db.prepareCall("commit");
> > > > CallableStatement cstmt = db.prepareCall("create global
 temporary
> > > > table temp_table (blobid NUMBER unique, blob_col BLOB) on commit
> > > > preserve rows");
> > > > cstmt.execute();
> > > > cstmt.close();
> > > > cstmt2.execute();
> > > > CallableStatement cstmt1 = db.prepareCall("insert into
 temp_table
> > > > values (1, empty_blob())");
> > > > cstmt1.execute();
> > > > cstmt1.close();
> > > > cstmt2.execute();
> > > > cstmt2.close();
> > > >
> > > > CallableStatement plsqlblock =
> > > > db.prepareCall(stringThatFillsInEmptyBlobInTempTable);
> > > > plsqlblock.execute();
> > > > plsqlblock.close();
> > > >
> > > > PreparedStatement pstmt1 = db.prepareStatement("select blob_col
 from
> > > > temp_table where blobid = 1");
> > > > ResultSet rset = pstmt1.executeQuery();
> > > > BLOB bl;
> > > > if (rset.next())
> > > > {
> > > > System.out.println("success."); //<--- This prints out.
> > > > bl = ((OracleResultSet)rset).getBLOB(1);
> > > > }
> > > > pstmt1.close();
> > > >
> > > > InputStream bis = bl.getBinaryStream();
> > > > int numBytes = 0;
> > > > byte[] theBytes = new byte[appropriateLength];
> > > > numBytes = bis.read(theBytes); ///*******EXCEPTION HAPPENS
> > > > HERE!!!!
> > > >
> > > >
> > > > I would also like to mention that when I change temp_table to be
 just
> > > > a regular table, everything works correctly.
> > > >
> > > > What's the problem, and how do I fix it?
> > > >
> > > > Thanks,
> > > >
> > > > Corrine
> >
> >

You don't need a temporary table. In Oracle readers don't block readers or writers and writers don't block readers. This type of programming is often seen in SQLServer because of the lack of concurrency. Using a regular table you will not see concurrency issues in Oracle. Jim Received on Sat Oct 04 2003 - 04:41:41 CEST