On Wed, Jul 10, 2019, at 3:20 AM, Lele Gaifax wrote: > Hi, > > I would like to find an automated way to collect all columns of any mapped > class which type is declared as > > ColType.as_mutable(ConcreteType) > > In an application I'm developing I use sqlalchemy-media to handle multi-media > "attachments" to avoid storing the actual media within the database. > > As an example, consider > http://sqlalchemy-media.dobisel.com/tutorials/image.html#defining-the-model, > where the Person class contains an "image" column defined approximately as > > class Person(Base): > ... > image = Column(Image.as_mutable(Json)) > > Inspecting the class, I find that the "type" of the image column is actually > "Json", so that alone does not help. I tried different strategies, but I could > not find a way to determine it is related to "Image". > > Basically, in pseudo code, I'd like to distill an helper function like > > def find_image_columns(base_class): > for cls in base_class.__subclasses__(): > m = class_mapper(cls) > for col in m.columns: > if <col is related to Image>: # this is my glass of water > yield cls, col > > > I followed the as_mutable() code path, and found that it installs various > "hooks" to achieve its goal, but could not figure out how I could "inspect" > those to find out the link with the Image class.
yeah there is not a "nice" way to do that now without some new feature being added to support that. If "Image" is your own type, I would include that "as_mutable" sets up additional state somewhere, column.info is one place. sorry there is not a better solution. > > As a last resort, I can easily go around all my models and put some kind of a > marker in the "info" slot of the relevant columns, and then check for that, > but I wonder if there is an less intrusive way... knowing and loving SA I bet > there is and it's just a matter of pronouncing the right incantation :-) > > Thank you in advance for any hint, > ciao, lele. > -- > nickname: Lele Gaifax | Quando vivrò di quello che ho pensato ieri > real: Emanuele Gaifas | comincerò ad aver paura di chi mi copia. > l...@metapensiero.it | -- Fortunato Depero, 1929. > > -- > 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 post to this group, send email to sqlalchemy@googlegroups.com. > Visit this group at https://groups.google.com/group/sqlalchemy. > To view this discussion on the web visit > https://groups.google.com/d/msgid/sqlalchemy/87lfx6pd8n.fsf%40metapensiero.it. > For more options, visit https://groups.google.com/d/optout. > -- 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 post to this group, send email to sqlalchemy@googlegroups.com. Visit this group at https://groups.google.com/group/sqlalchemy. To view this discussion on the web visit https://groups.google.com/d/msgid/sqlalchemy/fe519363-4cc3-483d-a65a-dd1cc62eb635%40www.fastmail.com. For more options, visit https://groups.google.com/d/optout.
