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SQLAlchemy has a new, easy declarative layer

A historic transcript from the #sqlalchemy IRC channel

<zzzeek_> deitarion: we just added a new declarative layer which removes a little of the verbosity, not sure if thats where you saw “too much boilerplate”

<justsomedood> woot, declarative layer part of SA? So not an extension?

<zzzeek_> its in ext/

<zzzeek_> we’ve had activemapper its just terrilby out of date

<justsomedood> way out of date

<zzzeek_> this is way smaller than activemapper

<zzzeek_> its 90 lines

<justsomedood> I ran into a lot of problems with it, and sent some fixes to johnathan but it ended up being too much work

<zzzeek_> i doubt this one has any big problems

<zzzeek_> since it does almost nothing :)

<justsomedood> hehehe

<Gedd> justsomedood: what kind of problems?

<justsomedood> It deferred class loading / table creation to make sure all dependencies were met before it did, that didn’t always work

<justsomedood> I ran into cases where if I didn’t define my classes in the correct order it would never create them, or get stuck in a loop

<justsomedood> I haven’t used it since 3.10-ish I think though

<Gedd> ah ok

<Gedd> that explains it :)

<NandoFlorestan> zzzeek_, the synonym stuff in the declarative layer is sweet!

<NandoFlorestan> I think this may be an Elixir killer

<jek> nah

<Gedd> NandoFlorestan: FWIW, Elixir handles synonyms too

<NandoFlorestan> hmm, didnt know that.

<zzzeek_> NandoFlorestan: elixir has a ton of stuff this does not

<justsomedood> So on this one, when defining “complex” relations(), with a primaryjoin on a table/object that hasn’t been defined yet you’d probably have to make that at the end with a class_mapper()?

<zzzeek_> you can stick it on later, like User.someprop = relation(SomeOtherObject,

<zzzeek_> theres no class_mapper() needed here really since the class goes right to the mapper.....its also there as class.__mapper__

<justsomedood> k

<justsomedood> cool

<justsomedood> it would definitly condense my models and make them easier for others to read, and I wouldn’t have to worry about the syntax changing

<justsomedood> me likes

<NandoFlorestan> that is why I like it: I already know the syntax