SQLObject 是一个流行的Python 数据库对象映射框架，映射的规则就是表->类、字段->属性
1. The lists of columns/indices/joins are now sorted according to the order of declaration.
2. "validator2" was added to all columns; it is inserted at the beginning of the list of... validators, i.e.
3. its from_python() method is called first, to_python() is called last, after all validators in the list.
4. SQLiteConnection's parameter "use_table_info" became boolean with a default value of True; this means the default schema parser is now based on PRAGMA table_info().
5. As a major API change, the "dirty" attribute was moved to sqlmeta