Why different engines in one database?

[hezjing]

Hi
When and why we create tables in different storage engines within a same
database?

Take for example a normal inventory application that provides CRUD operation
to
- USER table (e.g. create new user)
- STOCK table (e.g. when there is new stock arrives)
- CUSTOMER table (e.g. create new customer)
- SALE table (e.g. when a stock is bough by a customer)

I think it is always a best choice to use InnoDB since many applications are
transactional.

How would one wants to create a USER table in MyISAM engine and SALE table
in InnoDB engine?

Can you give some example?


Thank you!


-- 

Hez