Bubble is fairly SQL like, it is the Relational aspect that is probably a little different.
http://forum.bubble.io/t/sql-joins-vs-bubble/25806
Instead of a Foreign Key pointing from child > parent you can either a) embed the parent in the child b) embed a list of children in the parent c) do both. You then just navigate the join without having to explicitly code it (like an SQL join).
To switch paradigms here … the “embedded list” in bubble is a bit more like a collection of objects (bubble calls them things).
However this list is neither sorted nor ordered (it is more like a set than a bag or collection).
So if you want to have a many-to-many that is more like a join table that has attributes (so you can sort by date added, or add in other attributes that describe the relationship) then that is the way to go. But you don’t have to.