tags:

views:

56

answers:

1
+1  Q: 

What kind of queries a website like stackoverflow use?

Hi,

I am learning mysql join queries. To pratice, I decided to make tables for a website like stackoverflow. I made three tables basically. 

Question_Thread
    thread_id
    title
    username
    datetime
Question_Reply
    reply_id    
    thread_id
    text
Question_Text_Comment 
    comment_id
    reply_id
    comment

How do I query all the replies and comments of each reply? I can't find a relationship here. It is not many-to-many, one-to-many, or one-to-one. It looks like one-to-many because one reply have many comments. The problem is that question detail page have many replies.

please advise me...

+2  A: 

Question and reply is a one-to-many relationship. Reply and comment is a one-to-many relationship.

The properties (and keys) as far as I can see are looking good. I don't see the problem...

_NT  2009-10-23 10:09:21
so..do I have to query each reply's comments on question detail (the page you are viewing right now)? for example, if there are three replies and each of them have four comments. Do i have to query three times?
Moon  2009-10-23 10:31:25
No you don't have to. You can use an ORM to facilitate this, such as NHibernate, or Linq-to-Sql (which is what StackOverflow use), or other. This would allow you to do load the Question and its properties would contain the required data.But if you're using bare SQL queries, then yes, you would query three (or more) times. 1) Get Question, 2) Get Question's Replies, 3) Get all Comments for all retrieved Replies. Mind you, this is what ORM would do anyway, it is just abstracted for you not to worry to much about.
_NT  2009-10-23 10:56:57
ah! I thought there is a query that queries all replies and comments.
Moon  2009-10-23 11:09:54

related questions

Remove Quotes and Commas from a String in MySQL
What's the best way of converting a mysql database to a sqlite one?
How do you manage databases in development, test, and production?
Multiple foreign keys?
Add 1 to a field (MySQL)
Issues using MS Access as a front-end to a MySQL database back-end?
Bigger than a char but smaller than a blob
How do I retrieve my MySQL username and password?
Long-time LAMP Developer moving to VB.NET
How do I Concatenate entire result sets in MySQL?
Full complete MySQL database replication? Ideas? What do people do?
SQL: Distribution of table in time
SQLite vs MySQL
How do I create a new Ruby on Rails application using MySQL instead of SQLite?
Multiple Updates in MySQL
MySQL/Apache Error in PHP MySQL query
What all do I need to escape when sending a (My)SQL query?
Auto Generate Database Diagram MySQL
Mechanisms for tracking DB schema changes
How big can a MySQL database get before performance starts to degrade.
Python and MySQL
SQL Server 2005 implementation of MySQL REPLACE INTO?
How to export data from SQL Server 2005 to MySQL
Throw Error In MySQL Trigger
Binary Data in MySQL