There's a lot more to making categories and forums than just adding them to those tables.
First, there are also a lot of permission settings that go along with creating a new category/forum. If you are manually doing this you will also have to set this stuff up in the jforum_roles and jforum_role_values tables. This has to be done for every group you want this forum / category to be visible to. Se the initial data sql script for an example of this.
Second, all this information is cached in memory. So, just adding it to the DB will not update the memory cache. You will need to restart the jForum application for the new stuff in the DB to appear.
FWIW, the best practice for adding forums and categories is to use the Jforum system via some HTTPClient software (e.g. apache.org's Java packages.) This will add the forums with all the desired priviledges, etc. Plus the memory cache will be updated.
display_order is the order in which you want the categories to be displayed. There is an order by display_order asc clause on the selectAll query. forum_order is the same thing, except for forums.
[originally posted on jforum.net by monroe]
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