When I started coding the port from phpbb (
http://www.jforum.net/confluence/display/migration ), the start step was to look - surprise - to the table strucutres, and see the relations.
The table names are quite easy to guess ( jforum_topics for the topics, jforum_users for user, jforum_posts and jforum_posts_text for opsts and text etc ).
Next, we need to check the posts text. The main job is to see how jive handles bbtags and, if they differ from the way that jforum does, write some
java code to port it.
For example, phpbb put some hash in the tags, like [b:s386xda], and jforum does not. So, the migration utility had to remove these hashes before wrting to the database.
Also, date and time are slight as well, so some manipulation were also needed.
You can take a look in the source code:
https://jforum-tools.dev.java.net/source/browse/jforum-tools/phpbb2jforum/
Rafael
[originally posted on jforum.net by Rafael Steil]