Le mercredi 29 octobre 2014 14:16:23 Demai Ni a écrit : > Robert and Ronan, > > many thanks for your response. > > I realized there is no clean way/api for it. maybe a hacking of ptree can > do the trick.. :-) > > I will also take a look at IMPORT FOREIGN SCHEMA. However, for this > requirement, I still need the user to input filename or filefolder, and I'd > like to process the file(s) during create foreign table time, and save the > processed result somewhere like ftoptions column in pg_foreign_table. may > be some other way I can save the process result and make it assessable > during query time?
You can pass options to IMPORT FOREIGN SCHEMA. So, you could maybe implement it so that the user can do that: IMPORT FOREIGN SCHEMA public FROM SERVER file_server INTO local_schema OPTIONS (filename '/path/to/the/file'); Your FDW would then issue several CREATE FOREIGN TABLE statements, with all the necessary options. Or even, to allow importing multiple files at once: IMPORT FOREIGN SCHEMA public FROM SERVER file_server INTO local_schema OPTIONS (directory '/path/to/the/file_dir/'); > > Demai > > On Wed, Oct 29, 2014 at 10:01 AM, Ronan Dunklau <ronan.dunk...@dalibo.com> > > wrote: > > Le mercredi 29 octobre 2014 12:49:12 Robert Haas a écrit : > > > On Tue, Oct 28, 2014 at 5:26 PM, Demai Ni <nid...@gmail.com> wrote: > > > > I am looking for a couple pointers here about fdw, and how to change > > > > the > > > > > > option values during CREATE table time. > > > > > > > > I am using postgres-xc-1.2.1 right now. For example, it contains > > > > file_fdw, > > > > > > whose create-table-stmt looks like: > > > > CREATE FOREIGN TABLE t1(....) > > > > SERVER file_server > > > > OPTIONS(format 'text',filename 'testing.txt'); > > > > > > > > I would like to replace the 'testing.txt' with absolute path like > > > > '/user/testor1/testing.txt', and make sure the new value is saved in > > > > pg_foreign_table; the file_fdw_validator is used to validate the > > > > options, > > > > > > but is there a way to replace the optionValue here? And get the new > > > > value > > > > > > stored in pg_foreign_table? > > > > > > > > Thanks > > > > > > > > BTW, in my real use case, I am trying to interpret a hdfs file and > > > > would > > > > > > need to save some hostname/port information in the option value, which > > > > not > > > > > > necessary specified by user. > > > > > > I don't think there's going to be a clean way to do this. The > > > intention of the system is that the user-provided options are simply > > > stored, not that the FDW author is going to use the options list to > > > store their own bits and pieces. > > > > I would do that during the IMPORT FOREIGN SCHEMA statement. That way, the > > user > > doesn't have to specify those options: they would be generated at IMPORT > > time, > > and the user could change them later if really needed. > > > > -- > > Ronan Dunklau > > http://dalibo.com - http://dalibo.org -- Ronan Dunklau http://dalibo.com - http://dalibo.org
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