Nono #1 - Using text fields to link tables
So if you have a “Book” which has an Author, don’t make that field a text, and then search for “JK Rowling” in another table to find their details.
Give the Author field on Book a type of Author.
Nono #2 - Using Unique Id to link tables
Every thing in Bubble has a UniqueId.
But don’t store the UniqueID of your Author on the Book table as an alternative to #1
If you find yourself using the UniqueID to search for things … have a really good look for another way.
Nono #3 - Using Lists of Texts
This is rarely the right thing to do, you are usually better off listing a Recipe’s Ingredients as a separate table, and link to it, rather than “Flour, Eggs, Sugar”.
If this is a very trivial list, with no requirement to process the items further, then fine, but think before you do.
Nono #4 - Overusing Relational Database thinking
Bubble is not a relational database. Many apps do not use relational databases now. Getting obsessed with 3rd Normal Forms is waaaaay too much overthink.