hilo

Scenario: Hi/Lo is initialized for MyEntity with Lo 100 The table is empty. Two sessions with different connections have both inserted three items. TableIds 1 2 3 100 101 102 If a third one comes in at a later time and inserts three items: TableIds ... 200 201 202 Is there a way to not get these gaps? The Lo value is stored against the SessionFactory, not the Session. You only ever get gaps when you restart your application and create a new instance of the SessionFactory. A new Hi value is pulled from the database and stored in the SessionFactory, so if you have a web farm, each site will have

I have an issue on my hands that I've spent several days searching for an answer to no avail... We're using HiLo Id generation, and everything seems to be working fine, as long as the entity table is in the same schema as the hibernate_unique_key table. The table structure is pretty simple. I have my hi value table in the db as dbo.hibernate_unique_key. Several entity table are also in the dbo schema, and they work without issue. Then we have tables under the "Contact" schema (such as Contact.Person and Contact.Address). In the Person Mapping file: <class name="Person" table="Person" schema=

Just wanted to get some opinions on primary keys - would it be better to use identity/sequence numbers or use a HiLo strategy (query for the high value and increment the low value on the app itself)? If your application is only going to use one database, I'd go with an identity/sequence. The only really compelling reason to go with HiLo that I've seen is when you could have two disconnected instances of your application that people can work on simultaneously and you need to reconcile the differences at some point Ex . You are working on a content management system where people could be working

I've seen some docs by Fabio Maulo that shows the following params: <id name="Id" type="Int64" column="cat_id"> <generator class="hilo"> <param name="table">hi_value</param> <param name="column">next_value</param> <param name="max_lo">100</param> </generator> </id> However, on this question the poster uses a <param name="schema">... I'd like to be able to specify schema for the HiLo generator. Is there definitive documentation for all generator parameters? I've tried googling it without success. Another param to throw in the mix is <param name="where">TableName='CmsLogin'</param> This gives

I've genereated a schema for my (SQL 2005) db using SchemaExport, and it's created a table CREATE TABLE [dbo].[hibernate_unique_key]( [next_hi] [int] NULL ) ON [PRIMARY] When I try to add an entity, I get the error "could not read a hi value - you need to populate the table". What am I meant to do? edit: I've inserted a 1 into the table, and it seems to work. Is this the correct value to have in there? NHibernate expects to find a value that stores the current hi value in that table, ie it first runs something like: current_hi = [SELECT max(next_hi) FROM hibernate_unique_key]. So all you need

I work with a database that depends heavily on identity columns. However as we have now moved all applications over to NHibernate I wanted to look into using HiLo as seems to be recommended with NHibernate. Are there any strategies to do this, or any common problems to watch out for? If this is a question about migrating an existing application to hilos which previously used auto ids, and has old data in it which needs to be migrated... then this would be my best bet (not tried it though! - comments welcome!) : Change your column types ids to bigints find out highest id value currently in any