Because then if two users try to use the "Connect Tablets" feature or the library sync feature (or .msf files) and their libraries aren't based on the same library backup (meaning all of the song IDs in their tables are different), songs will be incorrectly matched between their devices. I don't want to automatically set the song ID field for all new songs as it can lead to these problems. The field should really only be used when people plan on having multiple tablets use the exact same song IDs for the songs they want to be matched up. The reason for the button to generate a song ID is so that on one tablet, they can assign a new song ID without having to remember which song ID they used last, and then they can assign that song ID to the other tablets they plan on connecting with.
As far as why I woiuldn't use song table ID as the default when hitting the plus button, that value is not guaranteed to be unique among all song IDs the user might have entered themself. Additionally, for new songs, a song ID isn't available yet, so I would be having to perform a database query to get the Max ID + 1 anyways. If I tightly controlled the field and didn't let users enter values themselves, something like that might work, but then it would cause issues when interacting with libraries that aren't identical. It also wouldn't add any value beyond the existing table ID then.
Mike
As far as why I woiuldn't use song table ID as the default when hitting the plus button, that value is not guaranteed to be unique among all song IDs the user might have entered themself. Additionally, for new songs, a song ID isn't available yet, so I would be having to perform a database query to get the Max ID + 1 anyways. If I tightly controlled the field and didn't let users enter values themselves, something like that might work, but then it would cause issues when interacting with libraries that aren't identical. It also wouldn't add any value beyond the existing table ID then.
Mike