On Fri, Sep 27, 2019, at 9:34 AM, Julien Cigar wrote:
> On Fri, Sep 27, 2019 at 09:03:53AM -0400, Mike Bayer wrote:
> >
> >
> > On Fri, Sep 27, 2019, at 6:26 AM, Julien Cigar wrote:
> > > On Thu, Sep 26, 2019 at 11:39:52AM -0400, Mike Bayer wrote:
> > > > that's not supported, I would suggest trying to solve your problem in a
> > > > different way.
> > > >
> > >
> > > Ok, that's what I thought.. thanks!
> > >
> > > I have a typical joined table inheritance, with Content being the "base"
> > > class, and childs as Document, Folder, Event, etc.
> > >
> > > I have added a transparent translation package with the "one translation
> > > table per entity" approach (also using joined table inheritance),
> > > and hybrid properties.
> > >
> > > So I have ContentTranslation being the "base" class, and childs like
> > > DocumentTranslation, FolderTranslation, EventTranslation, etc. which
> > > contain translation fields specific to each class.
> > >
> > > You helped me some weeks ago on this and I ended with (1), in which two
> > > relationships were added to every children of Content
> > > ("current_translation" and "translations"), and hybrid properties
> > > pointing to their dedicated translation class.
> > >
> > > It works well, the only minor issue is that I don't have any
> > > relationship on the base Content class (as you told me in the past that
> > > overriding relationships could be problematic).
> > >
> > > I made some modifications (2) in which the relationships are now
> > > prefixed with the class name, and added two properties which point to
> > > the class relationship, so that in the end:
> > >
> > > - Content has a "content_current_translation" and
> > > "content_translations" relationships, and two property
> > > "current_translation" and "translations" pointing to them
> > >
> > > - Document has a "document_current_translation" and
> > > "document_translations" with also two property current_translation and
> > > translations pointing to them, but the minor issue is that the
> > > content_current_translation is also joined loaded, which I'd like to
> > > avoid.. and I'm wondering what would be the best approach.
> > >
> > > I don't know if it's clear, but if it is not I could make a test case
> >
> > I'm not sure what the problem is, the code I can see has "lazy='joined'" in
> > some spots, you'd make that into "lazy='select'" if that's the lazy loading
> > you want.
> >
> > if this is some kind of automatic-generation issue where some of these
> > generations need to apply a different kind of default loader then you would
> > need to add parameterization to your code generation scheme, such as
> > additional arguments to your setup_relationships() function.
>
> The problem I have if that the "current_translation" should always be
> lazy='joined' within it's context.
>
> In the base class (Content) "current_translation" points to the
> "content_current_translation" relationship. In a child class (Document)
> "current_translation" points to "document_current_translation"
> relationship, but a child class also contain the
> "content_current_translation", as Document inherits from Content and
> that the property has already been setup.
> So both relationships are joinedloaded at the same time when I'm
> session.query(Document).
there's no way I'm going to parse that without spending a long time looking at
an example, sorry I know we keep coming back to this code that you've been
working on but it's not something i can keep in my head in the interim.
>
> For example when I'm querying for a Document SQLAlchemy generates two
> queries for the translations (1) and (2). The JOIN on the
> document_translation table should happend in (1).
>
> When I'm setting the mapping for a child class (Document, Event, Folder,
> etc) I'm looking for a way to either 1) remove the
> "content_current_translation" relationship or 2) disable joined loading
> for this relationship.
>
> But when I'm dbsession.query(Content) the "content_current_translation"
> must be joined loaded
so my vague understanding is that you want a certain relationship to joinedload
when its at the top level, but not joinedload when it's deeper down the stack,
is that the general idea?
there might be some ways to approach this but also I think you should be able
to override the relationship() entirely on your subclass, if that works. I just
tried getting a proof of concept going but it doesnt seem to illustrate the
thing I'm going for, I can't get it to generate too many joins to start with
for some reason.
There's also other possible ways such as setting up query.options() within a
before_compile() listener.
As always, this is way too complicated for me to understand from fragments
alone. I'm not even sure why my own simple proof of concept is doing something
that it's doing and I don't have time to pdb into joinedloader today.
>
> (1) https://gist.github.com/silenius/482f6a0f46427580aae12ba32b836ee5
> (2) https://gist.github.com/silenius/511f3069a871dd17d6e202c6b92edaf8
>
> >
> >
> > >
> > > (1)
> > > https://github.com/silenius/amnesia_multilingual/blob/master/amnesia_multilingual/builders.py
> > >
> > > (2)
> > > https://github.com/silenius/amnesia_multilingual/blob/dev/amnesia_multilingual/builders.py
> > >
> > > Thank you :)
> > >
> > > Julien
> > >
> > > >
> > > >
> > > > On Thu, Sep 26, 2019, at 11:25 AM, Julien Cigar wrote:
> > > > > Hello,
> > > > >
> > > > > I'd like to change a lazy property of an existing relationship (from
> > > > > 'joined' to 'noload'). I tried the following:
> > > > >
> > > > > mapper = orm.class_mapper(MyClass)
> > > > > prop = mapper.get_property('some_relationship')
> > > > > prop.lazy = 'noload'
> > > > >
> > > > > but it doesn't seems to work, as the property is still loaded
> > > > >
> > > > > Any idea if this is possible?
> > > > >
> > > > > Thanks,
> > > > > Julien
> > > > >
> > > > >
> > > > > --
> > > > > Julien Cigar
> > > > > Belgian Biodiversity Platform (http://www.biodiversity.be)
> > > > > PGP fingerprint: EEF9 F697 4B68 D275 7B11 6A25 B2BB 3710 A204 23C0
> > > > > No trees were killed in the creation of this message.
> > > > > However, many electrons were terribly inconvenienced.
> > > > >
> > > > > --
> > > > > SQLAlchemy -
> > > > > The Python SQL Toolkit and Object Relational Mapper
> > > > >
> > > > > http://www.sqlalchemy.org/
> > > > >
> > > > > To post example code, please provide an MCVE: Minimal, Complete, and
> > > > > Verifiable Example. See http://stackoverflow.com/help/mcve for a full
> > > > > description.
> > > > > ---
> > > > > You received this message because you are subscribed to the Google
> > > > > Groups "sqlalchemy" group.
> > > > > To unsubscribe from this group and stop receiving emails from it,
> > > > > send an email to sqlalchemy+unsubscr...@googlegroups.com.
> > > > > To view this discussion on the web visit
> > > > > https://groups.google.com/d/msgid/sqlalchemy/20190926152504.GB1535%40p52s.
> > > > >
> > > >
> > > > --
> > > > SQLAlchemy -
> > > > The Python SQL Toolkit and Object Relational Mapper
> > > >
> > > > http://www.sqlalchemy.org/
> > > >
> > > > To post example code, please provide an MCVE: Minimal, Complete, and
> > > > Verifiable Example. See http://stackoverflow.com/help/mcve for a full
> > > > description.
> > > > ---
> > > > You received this message because you are subscribed to the Google
> > > > Groups "sqlalchemy" group.
> > > > To unsubscribe from this group and stop receiving emails from it, send
> > > > an email to sqlalchemy+unsubscr...@googlegroups.com.
> > > > To view this discussion on the web visit
> > > > https://groups.google.com/d/msgid/sqlalchemy/dab6e523-675f-4a88-aa6d-c303360a50e6%40www.fastmail.com.
> > >
> > > --
> > > Julien Cigar
> > > Belgian Biodiversity Platform (http://www.biodiversity.be)
> > > PGP fingerprint: EEF9 F697 4B68 D275 7B11 6A25 B2BB 3710 A204 23C0
> > > No trees were killed in the creation of this message.
> > > However, many electrons were terribly inconvenienced.
> > >
> > > --
> > > SQLAlchemy -
> > > The Python SQL Toolkit and Object Relational Mapper
> > >
> > > http://www.sqlalchemy.org/
> > >
> > > To post example code, please provide an MCVE: Minimal, Complete, and
> > > Verifiable Example. See http://stackoverflow.com/help/mcve for a full
> > > description.
> > > ---
> > > You received this message because you are subscribed to the Google Groups
> > > "sqlalchemy" group.
> > > To unsubscribe from this group and stop receiving emails from it, send an
> > > email to sqlalchemy+unsubscr...@googlegroups.com.
> > > To view this discussion on the web visit
> > > https://groups.google.com/d/msgid/sqlalchemy/20190927102658.GA16334%40home.lan.
> > >
> > >
> > > *Attachments:*
> > > * signature.asc
> >
> > --
> > SQLAlchemy -
> > The Python SQL Toolkit and Object Relational Mapper
> >
> > http://www.sqlalchemy.org/
> >
> > To post example code, please provide an MCVE: Minimal, Complete, and
> > Verifiable Example. See http://stackoverflow.com/help/mcve for a full
> > description.
> > ---
> > You received this message because you are subscribed to the Google Groups
> > "sqlalchemy" group.
> > To unsubscribe from this group and stop receiving emails from it, send an
> > email to sqlalchemy+unsubscr...@googlegroups.com.
> > To view this discussion on the web visit
> > https://groups.google.com/d/msgid/sqlalchemy/31539116-6f4d-4ed3-84cd-e0111c5b69b0%40www.fastmail.com.
>
> --
> Julien Cigar
> Belgian Biodiversity Platform (http://www.biodiversity.be)
> PGP fingerprint: EEF9 F697 4B68 D275 7B11 6A25 B2BB 3710 A204 23C0
> No trees were killed in the creation of this message.
> However, many electrons were terribly inconvenienced.
>
> --
> SQLAlchemy -
> The Python SQL Toolkit and Object Relational Mapper
>
> http://www.sqlalchemy.org/
>
> To post example code, please provide an MCVE: Minimal, Complete, and
> Verifiable Example. See http://stackoverflow.com/help/mcve for a full
> description.
> ---
> You received this message because you are subscribed to the Google Groups
> "sqlalchemy" group.
> To unsubscribe from this group and stop receiving emails from it, send an
> email to sqlalchemy+unsubscr...@googlegroups.com.
> To view this discussion on the web visit
> https://groups.google.com/d/msgid/sqlalchemy/20190927133408.GB16334%40home.lan.
>
>
> *Attachments:*
> * signature.asc
--
SQLAlchemy -
The Python SQL Toolkit and Object Relational Mapper
http://www.sqlalchemy.org/
To post example code, please provide an MCVE: Minimal, Complete, and Verifiable
Example. See http://stackoverflow.com/help/mcve for a full description.
---
You received this message because you are subscribed to the Google Groups
"sqlalchemy" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to sqlalchemy+unsubscr...@googlegroups.com.
To view this discussion on the web visit
https://groups.google.com/d/msgid/sqlalchemy/956f4c7a-7e27-41ec-a623-a8d98b9d67a6%40www.fastmail.com.
