Re: Appending to a large object - Mailing list pgsql-jdbc

From Barry Lind
Subject Re: Appending to a large object
Date
Msg-id 3F31BFBC.9030104@xythos.com
Whole thread Raw
In response to Appending to a large object  (Ole Streicher <ole-usenet-spam@gmx.net>)
Responses Re: Appending to a large object
List pgsql-jdbc
Ole,

The outputstream interface is for reading only.  If you want to append
you are going to need to use the LargeObject interface.  This is
documented in the PostgreSQL Programmer's Guide.  See the section
titled:  PostgreSQL Extensions to the JDBC API.

thanks,
--Barry

Ole Streicher wrote:
> Hi,
>
> sorry for bothering you again.
>
> I want to append some data to a LargeObject, but I could not find out
> how to do that. When I simply do
>
> ResultSet rs = queryStmt.executeQuery();
> try {
>   if (rs.next()) {
>     int oid = rs.getInt(1); // or wherever my Id is
>     LargeObject obj = lobj.open(oid);
>     System.out.println("SIze is " + obj.size();
>     OutputStream os = obj.getOutputStream();
>     os.write(...); // here I want to append to the existing stream
>     obj.close();
>     dbConn.commit();
>   }
> } catch (SQLException e) {
>   dbConn.rollBack();
> } finally {
>   rs.close();
> }
>
> It is not appended to the stream but overwritten from the beginning.
> The LargeObject defines some variables SEEK_SET, SEEK_END, SEEK_CUR
> that seem to be useful for my purpose; however I could not find the
> method to use them.
>
> Can you give me a hint how I can append to an existing LargeObject
> (using the OutputStream interface)?
>
> Ciao
>
> Ole
>
> P.S. Is there a Java standard API documentation (javadoc-converted)
> of the extensions (es. LargeObject handling) available?
>
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