NextValue should NOT be a PK (it shouldn't be indexed at all), because it
will have a single row that will change constantly (in essence, it's
simulating a sequence in databases that don't have them)
Here's something on Lo values and separation of tables:
http://stackoverflow.com/questions/2192449/nhibernate-and-hilo-generator-how-to-design-key-tables/2202759#2202759
Diego
On Fri, Aug 20, 2010 at 18:20, nh_3478 <[email protected]> wrote:
> Okay, just incase this isn't clear enough for others and to make sure
> I understand, I created a new table called HiValue and a PK field
> named NextValue and seeded it with a default value of 0. In my hbm
> file for OrderHeader I now have:
>
> <generator class="hilo" >
> <param name="table">HiValue</param>
> <param name="column">NextValue</param>
> <!--<param name="max_lo">100</param>-->
> </generator>
>
> The max_lo property, is that just to indicate a max value?
>
>
> Also, all the tables use an ID field, at least in the examples I'm
> following, so am I supposed to use a seperate HiValue table for each
> table I have? Is that the proper way to ensure proper sequencing of
> ID numbers? So, for instance, I have two tables: OrderHeader and
> OrderItem; is it best practice to create, say, OrderHeader_HiValue and
> OrderItem_HiValue tables and seed them how I see fit (e.g. 0, 100,
> etc) for a starting ID value?
>
>
>
> btw, thanks for the link...
>
> On Aug 20, 1:15 pm, "Frans Bouma" <[email protected]> wrote:
> > http://www.nhforge.org/doc/nh/en/#mapping-declaration-id-generator
> >
> > see the snippet below 'hilo'. you have to create a table for the number
> and
> > add a row.
> >
> > FB
> >
> >
> >
> >
> >
> > > -----Original Message-----
> > > From: [email protected] [mailto:[email protected]] On
> Behalf
> > > Of nh_3478
> > > Sent: vrijdag 20 augustus 2010 22:04
> > > To: nhusers
> > > Subject: [nhusers] "Invalid object name 'dbo.hibernate_unique_key'."
> >
> > > I get a genericadoexception with error {"could not get or update next
> > > value[SQL: ]"}
> > > and InnerException: "Invalid object name 'dbo.hibernate_unique_key'."
> >
> > > I am following, to the T, the Nhibernate 2 book by Aaron Cure.
> >
> > > //mssql 2008 express edition with table
> > > OrderHeader
> > > PK = Id, type = int
> > > then the rest of values seen in the constructor below are also there.
> >
> > > //my OrderHeader.hbm.xml file
> > > <?xml version="1.0" encoding="utf-8" ?>
> > > <hibernate-mapping xmlns="urn:nhibernate-mapping-2.2"
> > > assembly="Ordering.Data" namespace="Ordering.Data" >
> > > <class name="Ordering.Data.OrderHeader, Ordering.Data"
> > > table="OrderHeader" schema="dbo" >
> > > <id name="Id" type="int" >
> > > <column name="Id" />
> > > <!--<column name="Id" length="4" sql-type="int" not-null="true"
> > > unique="true" index="PK_OrderHeader" />-->
> > > <generator class="hilo" >
> > > <!--<param name="max_lo">100</param>-->
> > > </generator>
> > > </id>
> > > <property name="Number" type="String"/>
> > > <property name="OrderDate" type="DateTime"/>
> > > <property name="ItemQty" type="Int32"/>
> > > <property name="Total" type="Decimal"/>
> > > </class>
> > > </hibernate-mapping>
> >
> > > //OrderHeader class snipet...
> > > namespace Ordering.Data
> > > {
> > > public class OrderHeader
> > > {
> > > private int _id;
> >
> > > public virtual int Id
> > > {
> > > get { return _id; }
> > > set { _id = value; }
> > > }
> > > ...
> >
> > > When I try to save using code like so, I get the aformentioned errors.
> >
> > > //code
> > > OrderHeader oh = new OrderHeader("10", DateTime.Now, 2,
> 105,
> > c,
> > > null, null, null);
> > > //oh.Id = 51;
> > > session.Save(oh);
> >
> > > Now, I have it boiled down to the hilo generator. If I remove the
> > generator
> > > from the hbm.xml file, and assign a value to oh.Id = 51, then my object
> > > saves and the row is inserted into the database. How do I get this
> > > generator to work, though??? I've also tried native, but then I get a
> > > different error that it can't INSERT into database using NULL
> ID...somehow
> > > the generator is NOT assigning a valid value to my ID in my OrderHeader
> > > class.
> >
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> > - Show quoted text -
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