Hi, I think the discussion is always useful but prefer it to be less polemic.
Am 25.08.10 12:43, schrieb Andreas Jung: > SQL can become *very complicated* - ever tried to understand complex > SQL queries of other people? Working with a proper database model > on the Python level is much easier. When mapping classes to relations, sure. OTOH. I have no problem understanding properly modelled relational schema. As Chris Date points out "a relation is an object". I'm not a big fan of SQL per se - I think it manages to make a travesty of the declarative approach and makes some things which should be easy tricky. Things are improving with things like windowing functions. > Yes, you are moving complexity from > SQL to Python and ORM configuration can be confusing as well. However > a descriptive model of a database in Python with its relations is much > easier to handle than dealing with it on the SQL layer directly. Depending on how the "mapping" (it's actually the generation of SQL on the fly) happens this can lead to extremely weird modelling. The SA modelling of subclasses is weird, incorrect in my view. At Europython Hannu Krosing showed some stats of direct access over the active record approach. From what I recall of Trac and Django the iterating over large sets can indeed present a bottleneck which only a good SQL query can remove. >> > ORM encourages lazy programming = problems later >> > down the line. > Nonsense - using SQLAlchemy for more than four years now in four or five > larger projects and it is a major win regarding productivity, software > architecture, implementation and testing. I think SA has the advantage over some approaches in that it lets you do all the schema in the database, gives you some control over whether queries should be lazy or not, etc. and letting you write handcrafted SQL when necessary (it's a great convenience not to have to write them for getters and setters). Nevertheless, any programmer working with a relational database should have a good understanding of the relational model and the core SQL constructs. Furthermore, in my view any good Python programmer should be prepared to look at other approaches; indeed, I think this is a core advantage of Python. The Muldis-D project (which is based on the Tutorial D pseudo language) and Hannu's proposed DORA both offer significant advantages over SQL and, therefore, SQL generation. Charlie -- Charlie Clark eGenix.com Professional Python Services directly from the Source >>> >>> Python/Zope Consulting and Support ... http://www.egenix.com/ >>> >>> mxODBC.Zope.Database.Adapter ... http://zope.egenix.com/ >>> >>> mxODBC, mxDateTime, mxTextTools ... http://python.egenix.com/ ________________________________________________________________________ _______________________________________________ Zope-DB mailing list Zope-DB@zope.org https://mail.zope.org/mailman/listinfo/zope-db
