Re: will foreign key improve select query performance

[Chris <dmagick(at)gmail(dot)com>]

petchimuthu lingam wrote:
> If i create foreign key references, whether it will improve the 
> performance in the select query?

Foreign keys are used to create integrity in the database, it won't 
affect select performance.

eg:

create table users (
  userid int primary key,
  username text
);

create table news (
  newsid int primary key,
  created_by int references users(userid)
);

That means that a news item cannot be created by a userid that doesn't 
exist.

http://www.postgresql.org/docs/current/interactive/tutorial-fk.html

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