About 15 years ago, I worked on a team with a product that used an object based database. No SQL didn't exist, but it was kind of in a similar vein. The database was a pure object storage and there was an index b-tree to make sense of it. We could store anything at all in the database. As long as it inherited from a specific class. It used the object serialization features of the language (Object Pascal) to read and write the data chunks. It had a query layer that allowed collection interrogation of data with specific values set. But, it was also very problematic. The structure was fairly chaotic. Ignoring the specific implementation, it taught me that databases - despite the rigidity of the storage mechanism, were a bloody good way to keep data organised. And SQL, despite the warts and inconsistencies of the major dialects, is actually a very powerful way to query data. When you strip away the integrity and the ability to easily pull data out in a uniform way, it makes things a lot less fluid.