mysql - Will I see performance gains by creating table relationships? -

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i understand benefits of using table relationships in order create constraints, such preventing row being deleted 1 table when related row in another.

but doing improve performance when running joined queries.

eg. suppose have innodb tables user , userinfo shown below:

    user    |field   |type        |null  |key    |default          |extra  --|id      |int(11)     |no    |pri    |                 |auto_increment |  |email   |varchar(700)|no    |       |                 | |  |password|varchar(255)|no    |       |                 | |  |active  |varchar(1)  |no    |       |n                | |  |created |timestamp   |no    |       |current_timestamp| | |   userinfo |  |field   |type        |null  |key    |default          |extra  --|user    |int(11)     |no    |pri    |                 |    |name    |varchar(100)|no    |       |                 |    |position|varchar(100)|no    |       |                 |     ...

is beneficial in terms of performance when running following query? 

select * user u join userinfo ui on u.id = ui.user

it's index might (and will) boost performance, not foreign key alone.

also: mysql creates foreign key indexes automatically innodb.


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