>> if IDs are not created by a single source, don't rely on auto incrementing IDs. Data design outlives programs, and environments by a long time. Circumstance

>> if IDs are not created by a single source, don't rely on auto incrementing IDs. Data design outlives programs, and environments by a long time. Circumstances change. So when I designed the db, there was a single database. But 30 years later we live in a world with smart phones. Making design decisions because of _current_ circumstances can bite you hard later on. Reading parent /child. Yes there are ways to mitigate the issue, but it's extra work and code to do so. Ultimately you need the parent id before you can add the children though.