As JPA is providing the interface to connect your Java application to the database, it is supposed to be just an interface doing so. In the other words, you have freedom in managing your database, by changing the DB-specific parameters and tuning the database.
In MySQL, as most people should know, there provides a choice of storage engine on each table. By using JPA, you can let the persistence provider to generate the table for you. It is easy and let the persistence provider determine the suitable configuration for you, both on table and on each field.
The default storage engine for table is InnoDB, as it supports transaction, row-locking and foreign keys where are needed by JPA. However, if you have a table that needs performance rather than data accuracy, you can manually change the storage engine to MyISAM before or after the persistence provider’s decision.
You can stop the persistence provider from generating the table, which you build your own table first, and just simply mapped all the things to the Entity.
