Yes, you are right, thank you, Mike. On Tuesday, January 21, 2020 at 6:33:39 PM UTC+3, Mike Bayer wrote: > > > > On Tue, Jan 21, 2020, at 6:39 AM, Andrei Pashkin wrote: > > Let's suppose I have a compiled SA expression statement which I want to > cache to avoid repetitive compilation. Let's also suppose that I can't use > "literal_binds" because I want to provide parameter values late, after > getting the compiled query from the cache. > > Is it somehow possible to inject values into compiled query without > executing it? > > Here is a full example: > https://gist.github.com/AndreiPashkin/9b497233e2a7668d0da67dc74d169812 > > > When you execute a compiled statement using Core there is always a > dictionary of parameters you pass along. Whatever parameters you put > here take precedence. in your example you're using bindparam() directly, > so this is the easiest case, just pass "id": > > def my_cached_thing(): > cache = {} > stmt = sa.select([User.__table__]).where(User.__table__.c.id == > sa.bindparam('id')) > def go(engine, id): > with engine.connect() as conn: > return > conn.execution_options(compiled_cache=cache).execute(stmt, id=id) > return go > > > # in your code > cached_lookup = my_cached_thing() > > for id in [1, 10, 15, 27, 19, 38]: > result = cached_lookup(engine, id) # will only compile the statement > once > # ... etc > > The above thing I did with the nested function etc. is arbitrary, just the > main point is, same statement object and same cache dictionary. as > stated before, 1.4 will hopefully have an improvement to make all of this > transparent. > > Also note you can use Core select() constructs etc with the ORM classes > directly: > > select([User]).where(User.id == bindparam('id')) > > > > > > > -- > 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 sqlal...@googlegroups.com <javascript:>. > To view this discussion on the web visit > https://groups.google.com/d/msgid/sqlalchemy/d06b2b8f-f267-463f-9bca-efc9b431e13c%40googlegroups.com > > <https://groups.google.com/d/msgid/sqlalchemy/d06b2b8f-f267-463f-9bca-efc9b431e13c%40googlegroups.com?utm_medium=email&utm_source=footer> > . > > >
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