Engine Types

InnoDB is a transaction-safe engine. It also support row level locking. It does not support full-text search.

MyISAM is a high-performance engine. It supports full-text searching, but does not support transactional processing or row level locking.

MEMORY is functionally equivalent to MyISAM, but data is stored in memory instead of on disk. It is extremely fast, and ideally suited for temporary tables.

A database can consist of tables each with different engine type. Foreign keys however can't span engine types. That is, a table using one engine cannot have a foreign key referring to a table that use another engine.