Index in mysql

[anand01]

hi all,

I have doubt on Index,I know Index are used to increase the performance of table but my question is
where to create Index whether primary key table or foreign key tables ?

[smantscheff]

If you use the InnoDB engine with foreign keys, both primary and foreign key tables must have indexes on the common key field. Even with other engines indexes in all tables linked by foreign keys will boost performance.

[anand01]

thanks smantscheff