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Some useful commands

How to change the engine type of a table :
>alter table reportsTransfer engine= innodb ;

How to add foreign key to a table :
>ALTER TABLE tbl_name
    ADD [CONSTRAINT symbol] FOREIGN KEY [index_name] (index_col_name, ...)
   REFERENCES tbl_name (index_col_name, ...)
   [ON DELETE {RESTRICT | CASCADE | SET NULL | NO ACTION}]
   [ON UPDATE {RESTRICT | CASCADE | SET NULL | NO ACTION}]

  e.g
  >alter table reportsTransfer add foreign key  reportsId (reportsInsertedId ) references reportsInserted (id)


Note
> Before adding a foreign key to table make sure both the tables ( Reference table and table having foreign key ) engine type = InnoDb .
>InnoDB does not check foreign key constraints on those foreign key or referenced key
values that contain a NULL column.
>Currently, triggers are not activated by cascaded foreign key actions.

Explain doesn't works with Delete and Update statement.

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