For e-commerce site this site or the example provided and discussed is referenced on nearly every blog on the topic of e-commerce database design
https://www.princeton.edu/~rcurtis/ultradev/ecommdatabase.html
For database design examples, I literally type the type of database + design into google and see the images
There are usually examples discussed on this site: stackoverflow — it is like a forum for programming questions…sometimes helpful
Another usually very helpful is : vertabelo
They provide full example with discussion on reasoning for various types of database models
Besides those, which I came across just by google searching and pouring over loads of search results, I also just again use google to find information on relational databases in general to just get an idea of what they are.
In my opinion, database design isn’t very difficult when using an example with explanation for the need for each data type and the relations between them.
After that I write it out on paper and and connect the different data types with lines as the examples on google results images would. Then I write it in another format on paper to see them in a different way to make it easier to enter it all into my bubble database.
After that I double check the bubble database against the paper versions using highlighter to keep track of all things.
Then I start building the pages that will use that data and as I think of things I add them. Also as I encounter problems with data retrieval I think how the database would make it easier and I usually end up adding a new datatype and making the relation so that I can retrieve the data easily.
I think ultimately, most of the aspects about bubble that cause trouble for non-coders like myself, include things like database design, UI and UX design as well as best practices to stay organized while developing, and all of which should be learned about outside of bubble.
Then once armed with a decent understanding of those topics, building in bubble and learning about how bubble works specifically is the best strategy. I spent a lot of time building in bubble before I thought to learn about UI & UX design as well as database and feel it was helpful, but ultimately time wasted as everything I built was pretty lousy in those regards.