Your requested sticker.

See the sticker pack URL

This just blow my database.

Welcome!

Thanks!

(How) can I order elements in a Set? pack = StickerPack.get(url=shortname) sticker_list = pack.stickers Now pack.stickers.order_by(Sticker.file_id)? Probably like this? stickers_list = orm.select(s for s in Sticker if s.sticker_pack and s.sticker_pack.url == shortname).order_by(Sticker.file_id)

Is that the way to do it?

Did it work for you?

You can have even more complex ordering condition using lambdas https://docs.ponyorm.com/api_reference.html#Set.order_by

Yes, It works.

Welcome!

@Mikkass Thanks.

Can I apply queries when getting elements from a Set attribute?

Can I apply queries when getting elements from a Set attribute?

Apperantly not

Summary: isinstance(pack, StickerPack) and orm.select(s for s in pack.stickers) results in TypeError: Cannot iterate over non-entity object

pack.stickers is of type orm.Set

Apperantly not

I think I can do that on python side, with: data["stickers"] = [_sticker_to_json(s, add_pack_info=False) for s in [s_ for s_ in pack.stickers if not "nsfw" in [t.string.lower() for t in s_.tags]][:include_stickers]]

But that kinda sucks.

I think I can do that on python side, with: data["stickers"] = [_sticker_to_json(s, add_pack_info=False) for s in [s_ for s_ in pack.stickers if not "nsfw" in [t.string.lower() for t in s_.tags]][:include_stickers]]

Top one is how I would expect to do it in pony, bottom is the pure python workaround.

What is the best way to do it? Doing it in-memory on python side is not what I really want to do...

In any case, here my relevant data stucture, but it didn't change much. class Sticker(db.Entity): file_id = Required(str) # BQADBAAD6QIAAqQW9AX8GaFqUwWnrgI emoji = Required(unicode) # ❓ sticker_pack = Optional('StickerPack', column='sticker_pack_url') tags = Set('Tag', cascade_delete=True) sticker_messages = Set('StickerMessage') tl_id = Optional(int, size=8) # The id field of the telegram api schema the apps use. tl_access_hash = Optional(int, size=8) # The access_hash field of the telegram api schema the apps use. PrimaryKey(file_id, emoji) class Tag(db.Entity): id = PrimaryKey(int, auto=True) user = Required(User, column='user_id') message_id = Optional(int) # Of the message with the text, the tag. None means it got added via web gui. sticker = Required(Sticker) string = Required(unicode) use_global = Required(bool, default=False) composite_key(user, sticker, string) class StickerPack(db.Entity): url = PrimaryKey(str) title = Required(str) owner = Required(User, column='owner_id') stickers = Set(Sticker) first_seen = Required(datetime, sql_default='NOW()')

At this moment there is a technical limitation, that only entity class can be used as a source of generator. We can overcome it, but other tasks were more important. If you want to select from a collection you need to use lambda syntax: result = pack.stickers.select( lambda s: ...)

I'll try that, and hope this will be added eventually. But indeed this is not the most urgent feature to have :D

Not quite sure how to write that query tho

lambda should return true for objects you want to select. like: student1.courses.select(lambda c: c.credits > 20 and "philosophy" in c.name.lower())

Oh. I see.

I removed the if ... else ..., so It will return a boolean.

But it seems lambda s: "nsfw" not in [t.string.lower() for t in s.tags] is not possible? Still failing with TypeError: LIST_APPEND() takes 1 positional argument but 2 were given

Try to use generator instead of list comprehension: (...) instead of [...]

Wow, it works

This concept of using (...) instead of [...] always confuses me

Apparently, we need to fix bytecode decompiling for [...] in last Python. They both should work. The fix should be pretty easy

I am using ... hold on

python3.5

To be exact: Docker, tiangolo/uwsgi-nginx-flask:flask-python3.5

Hi, I'm using pony and I want to return list of results from a function with the @db_session decorator. the results are the relations from one of my classes. however when I try to access the properties of those results outside the function I get pony.orm.core.DatabaseSessionIsOver: Cannot load attribute Ramal[2].ramal: the database session is over . How can I query all properties from those objects and return them to use them later?

Hi Federico Why don't you process the objects inside the db_session?

I was trying to modularize and save the results obtained in the search to be used in other functions.

what if you could convert the result to JSON?

How would I do that?

this is something we are working on now

glad to hear that, would it be a good idea to also add a way to copy the result to a python dictionary to be used outside the db_session?

thanks for the help, I'm really liking the orm!

glad to hear that, would it be a good idea to also add a way to copy the result to a python dictionary to be used outside the db_session?

Currently I do that myself

Currently you can use to_dict method of entity instance. You can get a query result and convert it to list of dicts using a list comprehension.

https://docs.ponyorm.com/api_reference.html?highlight=to_dict#Entity.to_dict

Currently you can use to_dict method of entity instance. You can get a query result and convert it to list of dicts using a list comprehension.

huh.

The limitation of to_dict is may be hard to convert deep nested structures

The limitation of to_dict is may be hard to convert deep nested structures

How does it handle timestamps?

I understiood not at all?

It should return attribute values as a dict values. It does not convert them to JSON-compatible values automatically. But when you call json.dumps you can pass default argument which is a function. You can pass a function which convert a timestamp to suitable representation

Right. Awesome once again

BTW, how is that migration mode going on?

awesome, thanks!

It is in process, we have some tests which a fail currently and want to fix them before release

The base functionality works already

Cuz I made a (for me) non-trivial DB change so I wanted to ask.

This is my old `Tag` schema https://editor.ponyorm.com/user/luckydonald/Tags_4

This is what I actually want https://editor.ponyorm.com/user/luckydonald/Tags

The difference is that I moved sticker into a subclass, and added anotherone with a stickerpack attribute

an example of to_dict and json.dumps

The difference is that I moved sticker into a subclass, and added anotherone with a stickerpack attribute

What I understood, Pony does that in one big table, distinguising it with a special row, telling it to be a specific class.

def account_page(): user = get_current_user() projects = Project.select(lambda p: p.user == user).order_by(desc(Project.updated_at)) account = user.to_dict(exclude=['id', 'password', 'balance']) return json.dumps({ 'account': account, 'projects': [dict(p.to_dict(exclude=['id', 'user', 'data'])) for p in projects] }, default=json_handler)

def json_handler(obj): if hasattr(obj, 'isoformat'): return obj.isoformat() elif isinstance(obj, UUID): return str(obj) else: raise TypeError("Unserializable object {} of type {}".format(obj, type(obj)))

What I understood, Pony does that in one big table, distinguising it with a special row, telling it to be a specific class.

So, I'd need to add a row for that? If I remember correctly thats type "text" and contains a string of the class name? In that migration I would need to fill in "StickerTag", right? (I still have the sticker attribute) And add another pack field?

I think that first version of migration tool will not support such a changes which move attributes between subclasses. But this migration is actually simple. The first change is adding classtype system column which Pony uses to distinguish between subclasses. The second one is adding pack column for PackTag.pack relation. So the SQL for migration looks like (I assume PostgreSQL is used): alter table "tag" add column "classtype" text; update "tag" set "classtype" = "StickerTag"; --for previous objects alter table "tag" add column "pack" int references "stickerpack" ("id");

I think that first version of migration tool will not support such a changes which move attributes between subclasses. But this migration is actually simple. The first change is adding classtype system column which Pony uses to distinguish between subclasses. The second one is adding pack column for PackTag.pack relation. So the SQL for migration looks like (I assume PostgreSQL is used): alter table "tag" add column "classtype" text; update "tag" set "classtype" = "StickerTag"; --for previous objects alter table "tag" add column "pack" int references "stickerpack" ("id");

I just love you guys!

I think that first version of migration tool will not support such a changes which move attributes between subclasses. But this migration is actually simple. The first change is adding classtype system column which Pony uses to distinguish between subclasses. The second one is adding pack column for PackTag.pack relation. So the SQL for migration looks like (I assume PostgreSQL is used): alter table "tag" add column "classtype" text; update "tag" set "classtype" = "StickerTag"; --for previous objects alter table "tag" add column "pack" int references "stickerpack" ("id");

If I still have an old version of that code which needs to run, can I change it anyway? Probably should default the classtype to "StickerTag", can that work?

Yes, I think if you add default value it should work with previous code without problems

Cool, because I have seperated everything between Dev and Production, well except the database :/ The DB is shared.

Maybe it is better to have two different database copies for Dev and Prod

That way you may be sure that you non-tested dev code does not delete all objects from the database

Yes, definitly. Probably I'll learn that as soon as I fry up the DB. Couldn't find a way to easily export/import all the data, so I instead make periodically backups of the postgres folder... ... .. . and hope nothing bad happens... (Yeah that is terrible, I know)

Maybe we need some dump/load functionality in Pony

Not sure if that should be part of pony (or pony core at least)

But It could indeed make switching Databases easy

I think making backup of entire database is outside of Pony scope. But maybe we should have a method to save content of a known entities into a big JSON file and then to load data from that file

That way it may be easier to populate a dev & test databases

I think making backup of entire database is outside of Pony scope. But maybe we should have a method to save content of a known entities into a big JSON file and then to load data from that file

You could still "abuse" that, to have something similar to a backup, yes