Just Because I read is the best practice. But rather I prefer just use an int for id as you said.

It is better to use object because it is more safe

Maybe the problem is caused by some bug in Pony. It would be helpful if you can show me the code that creates objects. If it is confidential you can send it as a personal message to me

Is not confidential.

Ok, then show the code of add_voucher method

I'll paste the code here if isn't a problem. (With pastebin of course)

As well as get_offer method

Sure

I'll paste the code here if isn't a problem. (With pastebin of course)

Or you can just upload as a file in telegram

Https://pastebin.com/LeGhyfnb

Tell me If you need to run the code. You will need the db.cvs file

But it has private data. So I will have to fake it.

Ok, I'll just look at code at first

When instantiating an entity with a foreign relation, can I specify the foreign key instead of passing another entity?

Yes, I just wrote about that

Pony allows to specify object id instead of object itself: phone2 = Phone(person=777, number='234-56-78') When Pony sees id value instead of object, it assumes that the object with that id value already exists inside the database. If this is not true, then the database will raise the error that you encountered. Specifying id value instead of object is an optimization trick which can be applied if a programmer does not want load object from the database, and wants to say to Pony: "hey Pony, the object with this id is already created, I guarantee that, don't waste your time for checking this". In general it is better to specify object itself instead of specifying id

That's great, thanks!

Is there an alternative to upgrading my Postgres 9.3 install to be able to use JSON with Pony?

Nevermind

Hello. Tell me why it does not work? a = select(p.name for p in Parts) a = a.filter(lambda p: "20" in p.name) print(a[😏) AttributeError: 'str' object has no attribute 'name'

print a[ : ]

Hello!

Cause lambda argument for filter function is p.name in your case.

Filter always gets what was the X in select(X for ...

Can I make it this way? a = select(p.name for p in Parts if "20" in p.name)

If you have version of pony 0.7.3 you can use where instead of filter, it will work as you want

Ofc you can

Wait

GOOD a = select(p.name for p in Parts) a = a.where(lambda p: "20" in p.name)print(a[😏)

Or not, need to check

a = select(p.name for p in Parts) a = a.where(lambda p: "20" in p.name) print(a[😏) It works

Okay then.

In query q = select(x.a for x in X if ...) q = q.filter(lambda arg: ...) q = q.where(lambda p: ...) The argument arg of q.filter refers to x.a, the result of select expression (the name of argument arg may be arbitrary) The argument p of q.where refers to loop variable name p of original select generator

understandably! Thank you!

Another question Why if a = select(p.name for p in Parts) text = "12" a = a.where(lambda p: text in p.name) QUERY : FROM parts p WHERE p.name LIKE concat('%%', replace(replace(replace(%s, '!', '!!'), '%%', '!%%'), '_', '!_'), '%%') ESCAPE '!' ['12'] if a = select(p.name for p in Parts) a = a.where(lambda p: "12" in p.name) print(a[😏) QUERY : FROM parts p WHERE p.name LIKE '%%12%%

why is added WHERE p.name LIKE concat('%%', replace(replace(replace(%s, '!', '!!'), '%%', '!%%'), '_', '!_'), '%%') ESCAPE '!'

Cause adding string variables right in sql query is dangerous

And it works different in pony, when pony sees constant and global variable

But tons of replace seem ugly, I agree)

anti sql injection ?

Yup

Affects the speed of the slave?

Slave?

Affects the speed of work?

Excuse me)

Because in SQL in order to check that a substring is a part of string you need to use LIKE operator. And LIKE operator has escape symbols % and _ which are treated in a special way. _ means "any symbol" and % means "any number of any symbols" If a substring is received from a column, it is possible that the substring contains these symbols. And then the result of LIKE would be incorrect. In order to prevent that, we need to replace each % to !% and each _ to !_. Then !% will be interpreted as just a single % symbol without any special meaning. The same is with _ In other words, this expression is the simplest expression which works corectly when p.name contains % or _ symbols

More actions always produces more additional time. But I think here you dont lose much. Anyway this things are important.

I understand. Thank You! You, well done)

Last question! Excuse me! I can not find it in the documentation. a = select(p.name for p in Parts) a = a.where(lambda p: "14" in p.name) a = a.where(lambda p: 14 == p.id) print(a[😏) WHERE p.name LIKE '%%14%%' AND 14 = p.id How to change AND to OR?

You should reorganize your code. You can chat me in PM, I can explain you there using our native language)

I can reorganize the code) I will not distract you.

Okay. Make it single select()

Currently, it is not possible to split OR between several lambdas. You need to write OR expression inside a single lambda a = a.where(lambda p: "14" in p.name or 14 == p.id)

Thanks again!!!

👌

Hi. My designer does not save the changes "Cascade Delete"

http://joxi.ru/a2XQlbGC1BeB4A

I put False in all tables and saved.

And opened a new window designer!

All tables are Default (True)!

Bug?

yes. it is.

Hi, Since raw primary keys can be used when creating an object and referencing a foreign key, would it make sense to allow the same for queries such as this: Review.select(lambda r: r.product == 1).count()

Hi Matthew, currently you can write it explicitly: Review.select(lambda r: r.product.id == 1).count() For me, it doesn't look too verbose, so I'm not sure we need to add implicit casting of id to specific object type

Agree, with .id it works fine :)

Hello. An incomprehensible mistake. I got the base. Pony writes an error when creating.

TypeError: Incorrect type of attribute: ?.?

class Order(db.Entity): id = PrimaryKey(int, auto=True) date = Required(date) date_shipping = Optional(date) sum_shipping = Optional(Decimal) sum_position = Required(Decimal) sum_discount = Required(Decimal) sum_all = Required(Decimal) value_position = Required(int) discount_percent = Required(Decimal) issued = Required(bool) note = Optional(str) client = Required('Client') shipping_method = Required('ShippingMethod') payment_method = Required('PaymentMethod') order_positions = Set('OrderPosition', cascade_delete=False) pre_order_positions = Set('PreOrderPosition', cascade_delete=False)

date_shipping = Optional(date) On this line!

https://pastebin.com/x8hKAi5P

I swapped the lines and everything worked !!! Why?

date_ship = Required(date) date = Required(date)

Video how it works!

The first version of code fails because you redefined date name meaning from date type to Order.date attribute, and then tried to set date (that is, Order.date) as a type for date_shipping attribute. At the moment when the exception is generated Pony does not know yet what is the attribute name, because Order class was not created yet and attribute descriptors didn't receive their name from the Order class initialization code

Didn't know what it could be!

Thanks.

Hello. I remember there was a framework called PonyJS. But now I can`t find any docs and repo for it. Is it still actual?

Hi, at this moment it is not actual, I hope we can revive it later.

But why?