Bookmarks are the key to effectively using Obsidian as a non-relational database. The virtues of approaching your notes this way are several, and I covered some in Freeing Your Thinking. In this article, I explore using Bookmarks to construct flexible, interactive Knowledge Trees to organize the information in your vault (not the files).
The article describes a system consisting of three domains: Living, Learning and Creating. The tree is built entirely on bookmarks, and consists primarily of views (saved filters/queries) of my data organized in nested groups.
You can read the article in these places: