The great thing about PostgreSQL is that it is hybrid. With http://www.postgresql.org/docs/9.1/static/hstore.html http://www.postgresql.org/docs/9.1/static/hst

The great thing about PostgreSQL is that it is hybrid. With http://www.postgresql.org/docs/9.1/static/hstore.html http://www.postgresql.org/docs/9.1/static/hstore.html you can put schemaless documents into the same database, even into the same table row as your usual relational data. You could start with a schema that's only a primary key and hstore for all other data (like a fully schemaless database), but over time extract important fields from the hstore into columns to add indexes, constraints or joins.