using nHibernate to insert a new object to SQL Server gives error about identity insert not being turned off

Question

I have been pulling my hair out on this for a couple of hours at least now.

So I am using nhibernate to map my db to my code. In the DB I have table called "Product" which has a column called "ProductId" which is the primary key and also marked as an identity column in sql server 2012.

My class' mapping with the Id columned defined as:

Id(x => x.ProductId, mapper => mapper.UnsavedValue(0));

However after creating a new Product object and trying to save it I get the following error and inner exception:

{"could not execute batch command.[SQL: SQL not available]"}

Cannot insert explicit value for identity column in table 'Products' when IDENTITY_INSERT is set to OFF.

The exception is pretty clear and the product Id is set to 0. How do I tell nHibernate to not supply the Id column when creating a new object in the database?

Any help greatly appreciated

thanks

score 2 · Accepted Answer · edited May 23 '17 at 12:06

The generator used for the "ID" must be native (or identity), i.e. driven by DB engine. The mapping should be like this:

Id(x => x.ProductId
  , mapper =>
  {
    mapper.UnsavedValue(0)
    mapper.Generator(Generators.Native)
    ..
  });

See

using nHibernate to insert a new object to SQL Server gives error about identity insert not being turned off

1 Answers1