The original CREATE TABLE statement, including all specifications and table options are stored by MySQL when the table is created. The information is retained so that if you change storage engines, collations or other settings using an ALTER TABLE statement, the original table options specified are retained. This enables you to change between InnoDB and MyISAM table types even though the row formats supported by the two engines are different.

Because the text of the original statement is retained, but due to the way that certain values and options may be silently reconfigured, the active table definition (accessible through DESCRIBE or with SHOW TABLE STATUS) and the table creation string (accessible through SHOW CREATE TABLE) may report different values.

For InnoDB tables, SHOW CREATE TABLE and the Create_options column reported by SHOW TABLE STATUS show the actual ROW_FORMAT and KEY_BLOCK_SIZE attributes used by the table. In previous MySQL releases, the originally specified values for these attributes were reported.