MyISAM engine used as a B + Tree index structure, leaf node is stored in the address data field of the data record. FIG MyISAM is the primary key index:
the InnoDB also be used as a B + Tree index structure, but the specific implementation manner, but with different MyISAM.
MyISAM index and data files are separate index file is saved only address data records. In the InnoDB table data file itself is a pressing B + Tree index structure of the organization, this tree's leaf node data field holds a complete data record. This index is the primary key of key data tables, so InnoDB table data file itself is the main index.
