Not to mention that you can hash arbitrary objects in a hash table with no mapping of any kind.

    hash at: key put: anObject

Databases are vastly more complicated and require me to completely disassembly the object graph anObject may contain into a set of tables and rows to store it, and then reassemble the graph from tables and rows back into their object form when fetching.

The second one commits to using a relational database, one often easily triples the size of the code base. There's nothing simple about that.