On 11/10/2016 05:24 AM, T Johnson wrote:
When I print a select statement, my bindparams show as %s instead of as named
params. What could be the cause of this?
myparam
BindParameter('myparamname', 'hello', type_=Unicode())
print(table.c.colname == myparam)
table.colname = :myparamname
print(select([table.c.colname]).where (table.c.colname == myparam))
SELECT table.colname
FROM table
WHERE table.colname = %s
I tried to construct a toy example and couldn't reproduce my issue. So if this
doesn't prompt any ideas, I'll work to reduce my repeatable example to
something minimal and postable.
The reason this is important to me is that the %s hid a mistake I made in
assigning the same name to two bindparams that should have had different
values. This caused the actual value that was used during execution to be
selected arbitrarily and produce undesirable results. Note that if I compiled
with literal binds and executed, then I always got both distinct values
(probably due to it using positional args) and received desireable results.
SQLite, MySQL and others use "format" (e.g. %s) as a default paramstyle,
so if your Table belongs to a MetaData that's bound to an engine of that
variety, you get %s.
One of many, many reasons that for years I've tried to hide the
documentation for "bound metadata" as much as possible, it's an almost
useless feature. Yet it survives in a blog posts and tutorials everywhere.
--
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
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