[spamizbad]

As one of the few devs who has actually switched databases (SQL Server to Postgres) -- without an ORM -- the biggest timesink was regression testing sanely and exporting/importing the data. Which you would have to do with an ORM anyway. The amount of time I spent re-writing a total of ~20 non-ANSI SQL queries and re-creating a handful of views (some of which were quite complex) was no more than 3 hours. And that would have gone by much faster had I been more familiar with Postgres at the time.

[Demiurge]

> regression testing sanely and exporting/importing the data. Which you would have to do with an ORM anyway

You can export data into ORM specific, database agnostic format, such as Django fixtures or SQLAlchemy fixtures, and test against the ORM. This is actually one of the key ORM features to leverage.