Pony ORM Release 0.7.3

In this release we have added the sort_by method of the Query object. At this point it is an alias of the order_by method. In the release 0.8 we are going to make a backward incompatible change and slightly modify the behavior of the order_by method. If you replace the order_by with sort_by it will continue working without any problems in this and future releases. There is no urgency to make this change – it is a preparation for the 0.8 release.

Here is the list of changes in this release:

New features

  • where() method added to the Query object
  • coalesce() function added
  • between(x, a, b) function added
  • #295: Add _table_options_ for entity class to specify engine, tablespace, etc.
  • Make debug flag thread-local
  • sql_debugging context manager added
  • sql_debug and show_values arguments were added to db_session
  • set_sql_debug function added as alias to (to be deprecated) sql_debug function
  • Allow db_session to accept ddl parameter when used as context manager
  • Add optimistic=True option to db_session
  • Skip optimistic checks for queries in db_session with serializable=True
  • fk_name option added for attributes in order to specify foreign key name
  • #280: Now it’s possible to specify timeout option in db.bind() method for SQLite, as well as pass other keyword arguments for sqlite3.connect function
  • Add support of explicit casting to int in queries using int() function
  • Added modulo division % native support in queries


  • Fix bugs with composite table names
  • Fix invalid foreign key & index names for tables which names include schema name
  • For queries like select(x for x in MyObject if not x.description) add “OR x.info IS NULL” for nullable string columns
  • Add optimistic checking for delete() method
  • Show updated attributes when OptimisticCheckError is being raised
  • Fix incorrect aliases in nested queries
  • Correctly pass exception from user-defined functions in SQLite
  • More clear error messages for UnrepeatableReadError
  • Fix db_session(strict=True) which was broken in 2d3afb24
  • Fixes #170: Problem with a primary key column used as a part of another key
  • Fixes #223: incorrect result of getattr(entity, attrname) when the same lambda applies to different entities
  • Fixes #266: Add handler to "pony.orm" logger does not work
  • Fixes #278: Cascade delete error: FOREIGN KEY constraint failed, with complex entity relationships
  • Fixes #283: Lost Json update immediately after object creation
  • Fixes #284: query.order_by() orders Json numbers like strings
  • Fixes #288: Expression text parsing issue in Python 3
  • Fixes #293: translation of if-expressions in expression
  • Fixes #294: Real stack traces swallowed within IPython shell
  • Collection.count() method now checks if session is alive
  • Set obj._session_cache_ to None after exiting from db session for better garbage collection
  • Unload collections which are not fully loaded after exiting from db session for better garbage collection
  • Raise on unknown options for attributes that are part of relationship