I've been using relational databases + object relational mappers for object persistence. I don't think this is a truly adequate solution for persistence, because it adds unnecessary overhead. It also forces me to fit objects in a table-like structure, which sometimes can't be done gracefully - it's like fitting a square in a circle - it won't work well.
Now, I am aware that there are object-oriented databases out there, but for one thing they lack support, and also the relational model works for most of the data - just not all of it.
So, are there DBMS that support both object-oriented and relational records? Ie: I would be able have records in a (relational) table or a collection of objects depending on what I am working on?
You may want to research NoSQL as an alternative to a typical relational store.
"...I am aware that there are object-oriented databases out there, but for one thing they lack support, and also the relational model works for most of the data - just not all of it."
This is an unfair statement!.. There are plenty OOP langs with adequate support and several relational models with support for all practical datatypes, including user-defined.
来源：https://stackoverflow.com/questions/3375779/object-oriented-relational-hybrid-database