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Connection 4
This is the relationship that connects an add-on to its main game entry. An m-n-relationship is needed, because we can never be sure that every add-on will only connect to one single main game. This connection on RG level (in opposition to connecting on G level) will allow for more fine-grained possibilities. Exemplary, we will be able to map an add-on that wasn't released on every platform the main game was.
The switch Commercial add-on shall be set to YES if the add-on was developed by paid staff in a commercial company, i.e. is of "commercial quality" (That doesn't mean it's good.).
The switch Authorized add-on shall be set to YES if the add-on was officially recognized by the publisher of the main game as an add-on to that game at the time of release.
The switch Significant change of main game shall be set to YES if the add-on, besides adding more content, changes the gameplay of the main game in a way that someone wanting to play the original game should know about. There is a description field, too, where the user shall describe why this switch was set to YES. An example of all that is the Diablo add-on Hellfire which not only brings an additional character class with which the main game can be completed, too, but also enhances the original game world with new items like shrines.
Connection x
Exemplary, Switzerland has four official languages: German with a population share of 63.7%, French with 20,4%, Italian with 6,5% and Romansh with 0,5%. If a user chose a Swiss nationality inside the database, we could do a pre-sorting of displayed data with language attribute (screen shots / R / publications) according to these languages, if the user wishes so.
Connection y
Using this we will, exemplary, be able to create a region "Europe" which we, naturally, will assign every European country to. This region shall then be assigned to every R, which was published identically throughout Europe. Or there is some R which were released identically in every German-speaking country. This would qualify for a region, too.