Or you can declare entities as class Enum(db.Entity): objects = Set("Object") deprecated = Required(bool, default=False) class Object(db.Entity): enum = Optional("Enum", cascade_delete=False) And work only with enums which retrieved as select(e for e in Enum if not e.deprecated) In that case instead of deleting you just set deprecated value to True

Hi. I'm thinking to store rgba colors. Is it efficient to create a composite primary key (or composite index ?) with the 4 values ?

Hey I have a question about delete hooks. Assume I have a many to many relationship between a and b and I want a cascading deletion between them in the sense that if after a deletion of a any b that that has an empty a set should also be deleted. I wondered how to do that and stumbled upon deletion hooks. but when I try to delete the "to be orphaned" bs in a's before delete hook I get the exception that a is marked for deletion. I worked around this by manually deleting b afterwards but i would prefer something automatic. What's the best way to solve this in pony

Hi Jan! It is too late to do this in before_delete hook, because at this moment the object is already disconnected from related objects. You need to do it before actual call to delete. This should work: from pony.orm import * db = Database('sqlite', ':memory:') class Foo(db.Entity): name = Required(str) bars = Set('Bar') def delete_with_bars(self): bars = list(self.bars) self.delete() for bar in bars: if not bar.foos: bar.delete() class Bar(db.Entity): name = Required(str) foos = Set('Foo') db.generate_mapping(create_tables=True) sql_debug(True) with db_session: f1 = Foo(name='f1') f2 = Foo(name='f2') f3 = Foo(name='f3') b1 = Bar(name='b1', foos=[f1, f2]) b2 = Bar(name='b2', foos=[f1]) b3 = Bar(name='b3', foos=[f1, f2, f3]) with db_session: f1 = Foo[1] f1.delete_with_bars() with db_session: Foo.select().show() Bar.select().show()

Pony don't have official migration support yet, we are working on it In the meantime you can try a tool written by @luckydonald https://github.com/luckydonald/pony_up

Hi, just a question about the online editor. According to the pricing information the basic plan includes unlimited private diagrams. I purchased it yesterday and I see now, that only 5 private diagrams are included. What kind of trap is this? 😕

Hi, just a question about the online editor. According to the pricing information the basic plan includes unlimited private diagrams. I purchased it yesterday and I see now, that only 5 private diagrams are included. What kind of trap is this? 😕

But isn't this illogical? I mean I understand when a column marked as Required will draw an error, but an Optional column? Strange anyway is that I deliver an empty string to PonyORM (i.e. {'test_from':''} and therefore I have a ConstraintError. The same for date fields.