I’ve come to the conclusion that, for me, ORMs are more detriment than benefit. In short, they can be used to nicely augment working with SQL in a program, but they should not replace it. Some background: For the past 30 months I’ve been working with code that has to interface with Postgres and to some extent, SQLite. Most of that has been with SQLAlchemy (which I quite like) and Hibernate (which I don’t). I’ve worked with existing code and data models, as well as designing my own. Most of the data is event-based storage (“timelines”) with a heavy emphasis on creating reports. Much has been written about the Object/Relational Impedance Mismatch. It’s hard to appreciate it until you live it. Neward, in his well known essay , lays out many cogent reasons why ORMs turn into quagmires. In my experience, I’ve had to deal directly with a fair number of them: entity identity issues , dual-schema problem , data retrieval mechanism concern , and the partial-object problem .…