Question

I have a comments section on a website i’d like to streamline a bit if possible so it’s not as much of an impact on the database. When a user selects a post, and if it has comments associated with it, it lists the comments. when the comments list, it fetches the username from another table. I store the id for the user in the comments table, and use that id to select the record from the users table. and displays as “user” said:

lets say i have 1000 comments on a post, it will hit the users table 1000 times to grab user names. I think this is probably a bad design. i thought of a few solutions, but don’t know what would be recommended in this situation.

should i just be storing the username inside the comments table?

should i store all of the usernames already called in a session array?

put all of the usernames in a file, and call from the file?

or is there another solution that i haven’t thought of?

i’m kind of confused. I thought i was doing the right thing by using the IDs in the comment table, and then using it to fetch the username, but after reading about a million posts on using less impact on the database, i’m starting to question myself.

WOW, thanks for all of the useful answers. here is the table scheme, i don’t know why i didn’t put in in originally.

comments table for jokes:

id | author_id | joke_id | date_created | body
---+-----------+---------+--------------+-----
1  |     3     |    2    | 2011-06-12   | this is a comment

and for the users:

id | user_name | password | email | date_joined | visible
---+-----------+----------+-------+-------------+---------
 3 |   booboo  | password | email | todays_date |    1

Answer 1

This is what JOINs are for – so that you can run a single query and efficiently get the combined information from multiple tables. E.g.:

SELECT comments.id, comments.content, users.name
FROM comments
JOIN users ON comments.user = users.id
WHERE comments.id in (1,2,3)

would look up the 3 comments with id 1, 2, and 3, plus also get the username of each commenter, and return rows that looked like this:

comments.id | comments.content  | users.name
------------+-------------------+---------
1           | "First comment."  | "Poster1"
2           | "Second comment." | "Poster2"
3           | "Third comment."  | "Poster3"