Re: COPY data into a table with a SERIAL column? - Mailing list pgsql-general

From David G Johnston
Subject Re: COPY data into a table with a SERIAL column?
Date
Msg-id 1413481095811-5823291.post@n5.nabble.com
Whole thread Raw
In response to Re: COPY data into a table with a SERIAL column?  (Steve Wampler <swampler@noao.edu>)
Responses Re: COPY data into a table with a SERIAL column?  (Rob Sargent <robjsargent@gmail.com>)
List pgsql-general
Steve Wampler wrote
> Let me generalize the problem a bit:  How can I specify that the default
> value of a column
> is to be used with a COPY command when some rows have values for that
> column and
> some don't?

If you provide a value for a column, including NULL, the default expression
is not evaluated.

COPY is dumb but fast.  If you need logic you need to add it yourself.
Either before the copy or copy into a temporary UNLOGGED table and write
smart SQL to migrate from that to the live table.

You can also put smarts into a trigger.

Personally I would generally stage all the data then write two INSERT INTO
... SELECT statements; one for the known values and one where you omit the
column and let the system use the default.

David J.





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