Discussion: what are the storage features and differences between innodb and myisam

myisam stores data in three files.MYD,.MYI,.FRM data files and index files are stored separately
innodb store data. Deposit FRM table definition,. ibd (exclusive table space), the ibdata (Shared table space). innodb Shared independent store data points table space and table space which determined by innodb_file_per_table variables (use), enjoys a tablespace storage ". ibd "file is used to store data, and each table 1". ibd "file, file stored in the same position and MyISAM data, be determined by datadir. If a Shared storage table space is chosen to store data, an ibdata file will be used, and all tables will use one (or more, configurable) ibdata file in common. ibdata files are available through innodb_data_home_dir and innodb_data_file_path
The two parameters together constitute the general directory where the innodb_data_home_dir configuration data is stored.

Note:
Although we can decide whether to use a Shared table space or a dedicated table space to store our tables, the Shared table space must exist, because Innodb's undo information and other metadata information are stored in the Shared table space.