On Wed, Oct 11, 2023, at 4:22 AM, Pierre Massé wrote: > Dear all, > > I have a requirement that makes me think that I need to "mass patch" some ORM > objects. However, I am open to any suggestions regarding the way to answer my > requirements. > > I have defined an ORM object which represents a user, holding longitude and > latitude (among other attributes). At some point, I want to query many of > those users, and send them back holding the geographical distance from a > certain point (defined by longitude and latitude) along with their other data. > > Computing the distance is computationally heavy, and I noticed that I could > greatly improve performance by mass computing those distances, using numpy > for example. > > My question is: would it be possible to split my flow in 2 : > - a flow that queries the data that is simply available in the database, as > ORM entities > - a flow that queries lon/lat as a numpy array, perform the distance > computation > and afterward merge those 2 in the queried ORM entities?
This is a straightforward programming task. Query for the set of objects you want, assemble the appropriate values into a numpy array, do wahtever numpy thing you need, then merge back. you'd likely want to ensure you can correlate numpy rows back to original objects most likely by keeping a sort order between your result set and your numpy array. not stated here is if these numpy-calculated values as assembled onto ORM objects are also database-column mapped, it sounds like they are not (otherwise those values would be in the database), so the matrix values can be applied to plain attributes on the objects directly. now where this may be more challenging, not sure if this is what you're asking, is if you want this to happen implicitly for all queries or something like that. there's ways to do this depending on the programming patterns you are looking to achieve however I'd certainly start simple with a function like "apply_lat_long_to_list_of_objects(obj)". > > It is important to me that I finally get back a list of ORM entities fully > populated, because my whole downstream process is built around this > assumption. > > Thanks a lot for your insights on the matter! > > Regards, > > Pierre > > PS: giving me a "SQLAlchemy fast distance computation" won't do the trick, > because I have other kinds of computations that may not be optimizable this > way. > > > -- > 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/CAH4TWVuJWP9WsSYNScPH%2BK9JJ3PqbOwxkm%3D_PXbPtYXzpBdvcg%40mail.gmail.com > > <https://groups.google.com/d/msgid/sqlalchemy/CAH4TWVuJWP9WsSYNScPH%2BK9JJ3PqbOwxkm%3D_PXbPtYXzpBdvcg%40mail.gmail.com?utm_medium=email&utm_source=footer>. -- 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/f7dcbd42-0509-46c5-b668-1a15a4834cab%40app.fastmail.com.
