MySQL supports several storage engines that act as handlers for different table types. MySQL storage engines include both those that handle transaction-safe tables and those that handle nontransaction-safe tables:
MyISAM manages nontransactional tables. It provides high-speed storage and retrieval, as well as fulltext searching capabilities. MyISAM is supported in all MySQL configurations, and is the default storage engine unless you have configured MySQL to use a different one by default.
The MEMORY storage engine provides in-memory tables. The MERGE storage engine enables a collection of identical MyISAM tables to be handled as a single table. Like MyISAM, the MEMORY and MERGE storage engines handle nontransactional tables, and both are also included in MySQL by default.
The InnoDB and BDB storage engines provide transaction-safe tables. To maintain data integrity, InnoDB also supports FOREIGN KEY referential-integrity constraints.