How to connect two databases(PHP , MySQL)

Hi Smismi,

The way a database works is it is split into multiple tables. Generally the way a forum works is it will hold any text in a table with a unique ID (even WF does it, the post ID of this is 9299917) So there is no difference so far between a new topic and a reply. Then you will have another column in this table with "parent" - this will tell you whether it's a new post, or a reply to someone elses post.

Something like this:
In your users table:
userID
username
password: (hashed password that no-one should see here)
email
etc etc, all as columns of the users table.

Posts table:
PostID:
UserID: (user who posted it)
Parent: (this could be a reply to another post, if there is nothing here we assume it's a new topic)
Title
Content:

So say I'm userID 78, and I reply to you and you have made a post earlier with PostID 20:

In the users table:
userID: 78
username: Shadoware
password: fjiurteyhf7853 (encrypted)
email: info@shadoware.net

userID: 77
username: TestAccount
password: fjiurteyhf7853 (encrypted)
email: test@shadoware.net

The in your posts table:

PostID: 20
UserID: 77
Parent:
Title: New Topic
Content: Hi this is a topic, you can tell because there is no parent!

PostID: 21
UserID: 78
Parent: 20
Title: RE: New Topic
Content: Hi this is a reply! You can tell because my parent is postID 20.

Then in your PHP, you'd load in all the posts without a parent (SELECT title FROM posts WHERE Parent IS NULL) to give you a topic list, then when you click on a topic, load in any with that parent and display them in topic format. Taking any information you need from the users table too.

No problem, what you're doing is some basic database normalisation. This ensures you don't duplicate or have un-needed data in your tables, and often helps with linking (we have the User ID in the posts table for example)

If you look up some simple database normalisation techniques I'm sure you will get the hang of it. (Some tutorials make it more complex and abstract than others, I prefer to just stick to it as a practical guideline)

While this appears to be a very reasonable answer to the OP's actual question, what many of us here are suggesting is that the best approach is to use multiple tables in a single database, rather than using multiple databases.

Yea i need to use data from 2 tables at same time and i will try to use JOIN queries... Thank You very much...