Graham just answered the where part.
Now, I'd love to hear the _arguments_ why your DBA would have a problem with
the table count.
Diego
On Tue, Sep 14, 2010 at 04:06, Thomas Koch <[email protected]> wrote:
> Hi Diego - do you have a link to a description of using the "where"
> parameter?
>
> I might ignore the table count but our DBA function would crucify
> me. :-)
>
> Regards
> Thomas
>
>
> On 13 Sep., 15:49, Diego Mijelshon <[email protected]> wrote:
> > That's easy to do, with the "where" parameter.
> > The main drawback is that you have to seed it manually when creating the
> > schema.
> >
> > Also, why would you care about the table count?
> > It's just an implementation detail; these tables act as sequences in
> > databases that don't support them (where they do, you can use seqhilo
> > instead)
> >
> > Diego
> >
> >
> >
> > On Mon, Sep 13, 2010 at 10:29, Thomas Koch <[email protected]> wrote:
> > > Nice trick. I am not sure I like the idea of having a separate table,
> > > though ... actually I am sure I dont like it. :-)
> >
> > > To begin with I was investigating whether or not it would be possible
> > > to have a separate row for each table.
> >
> > > That would of course require an extra column for the entity name. I
> > > did not find any solutions to this.
> >
> > > Thomas
> >
> > > On 13 Sep., 14:16, Jason Meckley <[email protected]> wrote:
> > > > the read/write of hilo uses a record level lock, so you don't need to
> > > > worry about 2 session pulling the same hi value. you can also
> override
> > > > the hilo table name in the mapping. I like to give each entity which
> > > > uses hilo it's own separate table.
> > > > Customer, Customer_HiLo
> > > > Order, Order_HiLo
> > > > Foo, Foo_HiLo
> >
> > > > On Sep 13, 3:44 am, Thomas Koch <[email protected]> wrote:
> >
> > > > > Well, using NHProf (why didn't I think of that before?)
> >
> > > > > So to answer my own question "no there is no reace condition"
> >
> > > > > Details:
> >
> > > > > 1)
> > > > > begin transaction with isolation level: Unspecified
> >
> > > > > 2)
> > > > > Reading high value:
> > > > > select next_hi
> > > > > from hibernate_unique_key with (updlock ,rowlock)
> >
> > > > > 3)
> > > > > Updating high value:
> > > > > update hibernate_unique_key
> > > > > set next_hi = 1590 /* @p0 */
> > > > > where next_hi = 1589 /* @p1 */
> >
> > > > > 4)
> > > > > Reading high value:
> > > > > select next_hi
> > > > > from hibernate_unique_key with (updlock ,rowlock)
> >
> > > > > 5)
> > > > > Updating high value:
> > > > > update hibernate_unique_key
> > > > > set next_hi = 1591 /* @p0 */
> > > > > where next_hi = 1590 /* @p1 */
> >
> > > > > 6)
> > > > > Inserting my order
> >
> > > > > 7)
> > > > > Insert an address
> >
> > > > > 8)
> > > > > commit transaction
> >
> > > > > The reason I am seeing two updates of the key table is that each
> > > > > entity gets its own high value.
> >
> > > > > Thomas
> >
> > > > > On 10 Sep., 14:05, Fabio Maulo <[email protected]> wrote:
> >
> > > > > > since the source of "high" is concentrated in one place.... ;)
> >
> > > > > > On Fri, Sep 10, 2010 at 8:58 AM, Thomas Koch <[email protected]>
> > > wrote:
> > > > > > > Hi - I use the hi-lo generator for my domain and have a
> question
> > > > > > > regarding its use in multiple processes.
> >
> > > > > > > I have a WCF project that is the primary power behind
> generating
> > > > > > > entities and saving them to the database with NHibernate and
> HI-LO.
> > > I
> > > > > > > also have an administrative application that sometimes generate
> > > > > > > entities for the domain.
> >
> > > > > > > Since these two applications live en separate processes, is
> there a
> > > > > > > risk here of them creating overlapping id's ?
> >
> > > > > > > As far as I have understood, each session factory will update
> the
> > > > > > > "hibernate_unique_key" table and generate ids based on the
> "high"
> > > > > > > value returned.
> >
> > > > > > > Can the reading and updating of this "next high value" be
> > > considered
> > > > > > > an atomtic operation even though its done in separate
> processes?
> >
> > > > > > > Regards
> > > > > > > Thomas
> >
> > > > > > > --
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> > > > > > --
> > > > > > Fabio Maulo- Skjul tekst i anførselstegn -
> >
> > > > > > - Vis tekst i anførselstegn -- Skjul tekst i anførselstegn -
> >
> > > > - Vis tekst i anførselstegn -
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