On Tue, May 15, 2018 at 12:06 PM, Tom Lane <t...@sss.pgh.pa.us> wrote: >> One can imagine extensions of the idea: for example, the header could >> actually be used to identify the columns, so the column order in the file >> doesn't matter. There could also be an "AS" syntax to allow the target >> field names to be different from the field names in the header. I have >> occasionally found myself wanting to ignore certain columns of the file. >> But these are all significantly more complicated than just looking at the >> header and requiring it to match the target field names. > > Yeah, and every bit of flexibility you add raises the chance of an > undetected error. COPY isn't intended as a general ETL facility, > so I'd mostly be -1 on adding such things. But I can see the value > of confirming that you're copying the right file, and a header match > check would go a long way towards doing that.
True. FWIW, I'm +1 on this idea. I think a header line is a pretty common need, and if you're exporting a large amount of data, it could be pretty annoying to have to first run COPY, and then do (echo blah,blah1,blah2; cat copyoutput.txt)>whatireallywant.txt There's a lot of value in being able to export from program A *exactly* what program B wants to import, rather than something that is close but has to be massaged. -- Robert Haas EnterpriseDB: http://www.enterprisedb.com The Enterprise PostgreSQL Company
