Setup cost is non trivial. Portability is typically poor. Custom SQL or optimizing bad SQL can sometimes be very difficult to do without completely breaking o

Setup cost is non trivial. Portability is typically poor. Custom SQL or optimizing bad SQL can sometimes be very difficult to do without completely breaking open the ORM. The promises of ORMs are typically not kept. I have always found a thin wrapper around JDBC or some other SQL driver is always sufficient in avoiding the code explosion of reading from/writing to SQL databases.