Re: How to use JDBC to update LargeObject

Satish Burnwal (sburnwal) wrote:
> I am using 8.1 Postgre JDBC. I want to know how can I use JDBC to
> update the contents of a LargeObject. For example, say I have created
> a LO for a file with 1 Mb of data. Later on, file contents have
> changed and are now just 100 kb and I want to update the LO. When I
> try to write to a large object using the method largeObject.write(byte
> [], off, len), it seems to be updating the first 100 kb data, not
> really replacing the existing 100 MB with the new data. pg_largeobject
> table still shows the same number of rows. Any idea how can I update
> the contents of a large object.

See manual, http://jdbc.postgresql.org/documentation/84/binary-data.html:

" To use the Large Object functionality you can use either the
LargeObject class provided by the PostgreSQL™ JDBC driver, or by using
the getBLOB() and setBLOB() methods.
Important

You must access Large Objects within an SQL transaction block. You can
start a transaction block by calling setAutoCommit(false). "

--
Heikki Linnakangas
EnterpriseDB http://www.enterprisedb.com