To partially clarify and answer my own question here (I was very tired
by the time I pasted this last night)
In the case of:
sa
.insert
(mytable
).values(myothertable.select().filter_by(foo=sa.bindparam("bar"))
This doesn't currently work because the bindparam required for the
select statement gets discarded. Having gone through the way SA
compiles statements, it appears that parameters are used to fill in an
insert statements values. The only way I can see of getting around
this is that at the time of adding the values, they bindparams are
extracted from the select and added to a new attribute on the insert
statement, and around the time of creating the ExecutionContext, they
are processed and added back into the query.
My previous question about getting both the column names and the
bindparams, I managed to solve by (duh!) getting the column names,
compiling the select statement and then getting the bindparams. I
would still be interested to know where the bindparams are stored in
an uncompiled select though. I couldn't work it out.
Sorry if all this is a little fuzzy. It's my first time at really
trying to understand what SA does behind the scenes.
Thanks
Ed
On 11 Feb 2010, at 22:23, Ed Singleton wrote:
I've been having a clumsy hack at enabling myself to pass a select
statement as a value to an insert statement. IE:
sa.insert(mytable).values(myothertable.select())
I've got it working in that most basic case, but I'm struggling when
the select statement has bindparams. The insert needs to take them,
as well as (for some dialects) the column names of the select. The
thing is I can work out how to get the bindparams from a compiled
statement, and I can work out how to get the column names from a
uncompiled statement, but I can't work out how to get both from one
or the other. Any hints on this would be appreciated.
Also, I slightly worried that there's an obvious reason why this
hasn't been done before. Is there something stupid I'm missing? If
anyone's tried patching SA to do this I would greatly appreciate any
advice.
Thanks
Ed
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