We create converters to the most popular forum boards and we cannot find table relationships for importing data into phpBB3. Example: We need to know that when we as a forum to the forum table what other tables that we need to create data for etc... Has anyone created a diagram of this type of information in detail? Even written documentation of this would help. We do the conversions outside of php so that we can handle very large and complex boards. We upload our converted tables to the target board and create the forum from there.
I have once been searching for this kind of documentation too, but haven't found it yet. This might be of help, but I guess it is focussed on phpBB 3.0 mainly: https://wiki.phpbb.com/Tables