Comment by austin-cheney

Thinking small. In SQL databases a well put together database instance will typically have tables that with a single incrementing primary key column and some secondary key columns that point to unique records on other tables. That is the relational part of RDBMS.

Its not about what it looks like. Arrays have fancy functional methods, but not object structures. Its more about whether it executes faster and comprises fewer steps to read/write. A real case in my application is get all ports associated with unencrypted sockets associated with servers of a given type and sort the output in a manner chosen by the user. The data in this case is in different unrelated objects whose properties point to each other in various ways by identity, because each server and socket uses hashes for unique identifiers.