typically I load all the records I'm going to be working with at once, and
assemble them into dictionaries or other data structures so that as I process
the csv data, I can look things up in the local dictionary for the modify.
if the data you get from your CSV can all relate to the primary key of the
objects, then you can use session.merge(), applying the existing primary key to
a new object, which will be merged into the state of the existing row. This
also emits a SELECT for those rows, but again if you load them up ahead of
time, the check is against the local identity map.
On Oct 13, 2014, at 2:22 AM, James Hartley jjhart...@gmail.com wrote:
I have a CSV file with lots of redundant data which models many-to-many
relationships. I'm needing to scrub the data as it is inserted into the
database littered with unique constraints. Is there a way to insert the data
once without querying for each object before inserting?
I'm sure this is a common CSV translation nit, but it is new to me.
Thanks for any insight provided!
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