> On 19 Oct 2001 08:34:47 -0200, Marcus Brito wrote:
>
> >> As an alternative to fetching the parameters from the original definition
> >> as above, you can use
> >> SELECT last_value FROM seqname;
> >> to obtain the last value allocated by any backend.
> >
> >You can't trust this. Perhaps some other process (other bean, other
> >application, other thread) has alredy modified the sequence.
yes you can. thats the whole idea. sequences will have a cache, when you
first query a sequence in a connection, you will be given the first of the
cache. the cache will be per-connection, and you wont have to worry about
other processes.
as far as portability is concerned, if you're happy to limit yourself to
dbs with sequences, you can easily have a config switch, or even have the
sql in the config itself... there are plenty of options.
cheers
dim
> >
> >Suppose you have a table named MYTABLE, with a column named TBL_ID,
> >whose value is obtained from the SEQ_TBL_ID sequence.
> >
> >If you do something like:
> >
> >PreparedStatement stmt =3D dbConn.prepareStatement("INSERT INTO mytable(tbl=
> >_id) VALUES (nextval('seq_tbl_id'))");
> >stmt.executeUpdate();
> >
> >you should do the following (in JBoss) to get the value just inserted
> >
> >int oid =3D ((org.postgresql.Statement)(((org.jboss.pool.jdbc.PreparedState=
> >mentInPool)stmt).getUnderlyingPreparedStatement())).getInsertedOID();
> >
> >and then
> >
> >stmt =3D dbConn.prepareStatement("SELECT tbl_id FROM mytable WHERE oid =3D =
> >?");
> >stmt.setInt(1, oid);
> >ResultSet rs =3D stmt.executeQuery();
> >rs.next();
> >int tbl_id =3D rs.getInt("tbl_id");
> >
> >This is pretty ugly, specilly the line to obtain the inserted OID. So
> >many typecasts. Also, this is not portable across application servers.
> >But is the only way to make sure you obtain the last value you inserted.
> >If I'm wrong, please someone correct me.
> >
> >--=20
> >Ja ne,
> > Pazu
> > mailto: [EMAIL PROTECTED]
> >
> >Anime Gaiden: de f=E3s para f=E3s, sempre.
>
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