> On 25 Mar 2017, at 10:58, Brice PARENT <cont...@brice.xyz> wrote: > > Hello! > > Hello!
> If I had to provide a unified way of dealing with data, whatever its source > is, I would probably go with creating an standardized ORM, probably based on > Django's or PonyORM, because: > > - it doesn't require any change in the Python language > > So we basically want to be just like PonyORM (the part that executes comprehensions against objects and databases), except we find that the current comprehension syntax is not powerful enough to express all the queries we want. So we extended the comprehension syntax, and then our strategy is a lot like PonyORM. > - it allows queries for both reading and writing. I didn't see a way to write > (UPDATE, CREATE and DELETE equivalents), but maybe I didn't look right. Or > maybe I didn't understand the purpose at all! > > Good point! This is a hard one, a single query in PythonQL can go against multiple databases, so doing updates with queries can be a big problem. We can add an insert/update/delete syntax to PythonQL and just track that these operations make sense. > - it makes it easy (although not fast) to extend to any backend (files, > databases, or any other kind of data storage) > > Going to different backends is not a huge problem, just a bit of work. > - as a pure python object, any IDE already supports it. > > - It can live as a separate module until it is stable enough to be integrated > into standard library (if it should ever be integrated there). > > So we live as an external module via an encoding hack :) > - it is way easier to learn and use. Comprehensions are not the easier things > to work with. Most of the places I worked in forbid their use except for > really easy and short cases (single line, single loop, simple tests). You're > adding a whole new syntax with new keywords to one of the most complicated > and less readable (yet efficient in many cases, don't get me wrong) part of > the language. > Yes, that’s true. But comprehensions are basically a small subset of SQL, we’re extending it a bit to get the full power of query language. So we’re catering to folks that already know this language or are willing to learn it for their daily needs. > I'm not saying there is no need for what you're developing, there probably is > if you did it, but maybe the solution you chose isn't the easier way to have > it merged to the core language, and if it was, it would really be a long > shot, as there are many new keywords and new syntax to discuss, implement and > test. > Yes, we started off by catering to folks like data scientists or similar folks that have to write really complex queries all the time. > But I like the idea of a standard API to deal with data, a nice battery to be > included. > > Side note : I might not have understood what you were doing, so if I'm > off-topic, tell me ! > > -Brice > Thanks for the feedback! This is very useful. > > Le 24/03/17 à 16:10, Pavel Velikhov a écrit : >> Hi folks! >> >> We started a project to extend Python with a full-blown query language >> about a year ago. The project is call PythonQL, the links are given below in >> the references section. We have implemented what is kind of an alpha version >> now, and gained some experience and insights about why and where this is >> really useful. So I’d like to share those with you and gather some opinions >> whether you think we should try to include these extensions in the Python >> core. >> >> Intro >> >> What we have done is (mostly) extended Python’s comprehensions with group >> by, order by, let and window clauses, which can come in any order, thus >> comprehensions become a query language a bit cleaner and more powerful than >> SQL. And we added a couple small convenience extensions, like a We have >> identified three top motivations for folks to use these extensions: >> >> Our Motivations >> >> 1. This can become a standard for running queries against database systems. >> Instead of learning a large number of different SQL dialects (the pain point >> here are libraries of functions and operators that are different for each >> vendor), the Python developer needs only to learn PythonQL and he can query >> any SQL and NoSQL database. >> >> 2. A single PythonQL expression can integrate a number of >> databases/files/memory structures seamlessly, with the PythonQL optimizer >> figuring out which pieces of plans to ship to which databases. This is a >> cool virtual database integration story that can be very convenient, >> especially now, when a lot of data scientists use Python to wrangle the data >> all day long. >> >> 3. Querying data structures inside Python with the full power of SQL (and a >> bit more) is also really convenient on its own. Usually folks that are >> well-versed in SQL have to resort to completely different means when they >> need to run a query in Python on top of some data structures. >> >> Current Status >> >> We have PythonQL running, its installed via pip and an encoding hack, that >> runs our preprocessor. We currently compile PythonQL into Python using our >> executor functions and execute Python subexpressions via eval. We don’t do >> any optimization / rewriting of queries into languages of underlying >> systems. And the query processor is basic too, with naive implementations of >> operators. But we’ve build DBMS systems before, so if there is a good amount >> of support for this project, we’ll be able to build a real system here. >> >> Your take on this >> >> Extending Python’s grammar is surely a painful thing for the community. >> We’re now convinced that it is well worth it, because of all the wonderful >> functionality and convenience this extension offers. We’d like to get your >> feedback on this and maybe you’ll suggest some next steps for us. >> >> References >> >> PythonQL GitHub page: https://github.com/pythonql/pythonql >> <https://github.com/pythonql/pythonql> >> PythonQL Intro and Tutorial (this is all User Documentation we have right >> now): https://github.com/pythonql/pythonql/wiki/PythonQL-Intro-and-Tutorial >> <https://github.com/pythonql/pythonql/wiki/PythonQL-Intro-and-Tutorial> >> A use-case of querying Event Logs and doing Process Mining with PythonQL: >> https://github.com/pythonql/pythonql/wiki/Event-Log-Querying-and-Process-Mining-with-PythonQL >> >> <https://github.com/pythonql/pythonql/wiki/Event-Log-Querying-and-Process-Mining-with-PythonQL> >> PythonQL demo site: www.pythonql.org <http://www.pythonql.org/> >> >> Best regards, >> PythonQL Team >> >> >> >> >> >> >> _______________________________________________ >> Python-ideas mailing list >> Python-ideas@python.org <mailto:Python-ideas@python.org> >> https://mail.python.org/mailman/listinfo/python-ideas >> <https://mail.python.org/mailman/listinfo/python-ideas> >> Code of Conduct: http://python.org/psf/codeofconduct/ >> <http://python.org/psf/codeofconduct/> > > _______________________________________________ > Python-ideas mailing list > Python-ideas@python.org > https://mail.python.org/mailman/listinfo/python-ideas > Code of Conduct: http://python.org/psf/codeofconduct/
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