Our company is an ISV. Our application allows our clients to generate invoices. Our application uses an identity column to generate invoice numbers.

If we move our app to SQL Azure, many separate companies will need to be able to generate their own sequential invoice numbers from within a federated database.

Federations do not support the identity property, but this problem must have been solved already as it is so common. I imagine an invoices table will be federated on CompanyId (bigint). The invoices table will include many companies, each of which will require their own sequence of invoice numbers.

Is anyone able to point me to best practice in dealing with this issue? I must stress our clients expect sequential numeric invoice numbers.

Hello,

The following thread about similar issue and you can refer to the methods as Herve Roggero or JuneT post to get the sequential column in SQL Azure federation:
http://stackoverflow.com/questions/9642916/efficient-way-to-generate-sequential-numbers-on-sql-azure-federations

Regards,
Fanny Liu