On Wed, Nov 8, 2017 at 1:57 PM, <char...@konversion.ca> wrote: > So I'm trying to add support for Views, following a few recipes like this, > and this. > > Beyond the DDL element, I'd like greater integration with higher level > SQLAlchemy abstractions. > > For example, using the first recipe, the view isn't registered with the > metadata. > So while there is a table-like construct associated with the view, it isn't > really integrated with SQLAlchemy table-management facilities. > Tables on which the view depends can't be dropped through the `Table.drop` > or `Metadata.drop_all` methods, since they don't cascade. > So the `Metadata.drop_all` method is now broken.
I don't understand. The wiki example runs MetaData.drop_all() as the last step. The view is dropped because it *is* associated with the MetaData via the "before-drop" hook. I can offer general guidance on the other requests here but I would need specific runnable code illustrating how "drop_all" is broken to understand fully what you are trying to do. If you'd like the view to be associated as a drop with all the individual Table objects as well, then add a before-drop linking to each of those table objects. This could be automated by looking for all those Table objects in the given selectable when the view is first made. > > Basically, I'd like to be able to implement the `Table ` "interface" for > views(i.e. methods like `drop` and `create`). Is it possible? Any pointers > for that? The recipe makes use of TableClause, you can subclass it and add a create() and drop() method to it which calls upon CreateView() / DropView(), if you want the "checkfirst" part you can also use inspect(engine).get_views() (probably didn't exist whe this recipe was made) to see if the view exists first. > > Also, the first recipe uses the "_make_proxy" private method to create a > TableClause from the selectable. That method is undocumented(and obviously > private), > so I don't really like having that in production code. Is there an > alternative pattern suitable here? Not at the moment, _make_proxy can be made public across the board if folks want to work on writing good test suites and documentation for it. > > Is there any chance of seeing views officially supported by SQLAlchemy at > some point? Absolutely, with proper contributions it would be great to have a full featured view object but I would expect that contributors would be willing to provide tests, draft documentation, as well as some level of support in triaging and solving bugs discovered once released. Since views right now work pretty much fully (sans the examples of "not working" you'll show me) it's been less burdensome on the project to have views be just an application of existing event and compiler hooks, since it's easier to maintain those hooks rather than the full set of features a "View" object would. > > -- > 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. > 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. For more options, visit https://groups.google.com/d/optout.
