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Posted to derby-user@db.apache.org by Geoff hendrey <ge...@yahoo.com> on 2007/09/22 21:40:55 UTC

when does a ResultSet actually retrieve a BLOB

Hi,

if I have a column in a ResultSet, and the column is a BLOB, when does Derby actually send the BLOB to the JDBC client?

A) Before rs.next() is called?
B) when rs.next() is called?
C) when rs.next().getBlob(i) is called?


thanks.

Re: when does a ResultSet actually retrieve a BLOB

Posted by Knut Anders Hatlen <Kn...@Sun.COM>.

Geoff hendrey <ge...@yahoo.com> writes:

> Hi,
>
> if I have a column in a ResultSet, and the column is a BLOB, when does Derby actually send the BLOB to the JDBC client?
>
> A) Before rs.next() is called?
> B) when rs.next() is called?
> C) when rs.next().getBlob(i) is called?

Derby 10.2 fetches the entire BLOB when rs.next() is called. Derby 10.3
uses a different mechanism based on locators and doesn't fetch it until
you need it (for instance when you call Blob.getBytes()).

-- 
Knut Anders