What is the best default transaction isolation level for an ERP, if any?

Question

Short background: We are just starting to migrate/reimplement an ERP system to Java with Hibernate, targeting a concurrent user count of 50-100 users using the system. We use MS

Answer 1

For SQL Server (and probably most major RDBMS), I'd stick with the default. For SQL Server, this is READ COMMITTED. Anything more and you start overtaxing the DB, anything less and you've got consistency issues.