Thread: Column descriptions - could they be propagated to new tables?
Since I discovered the facilities in Postgres for providing and listing
column descrptions, I have found them very useful, especially for adding a
string showing physical units to my columns. For example:
\d+ cat
Table "public.cat"
Column | Type | Modifiers | Description
-----------------+------------------+-----------+--------------
src_num | integer | |
ra | double precision | | deg
decl | double precision | | deg
radec_err | real | | arcsec
lii | double precision | | deg
bii | double precision | | deg
pn_cts | real | | counts
However if one performs a JOIN creating a new table, all these
descriptions fail to transfer. I haven't been able to find any easy way
of propagating the descriptions - would it be a useful facility to have
them propagated automatically? I would have thought that things like
units would be useful even in many scientific applications, e.g. to have
monetary columns described as dollars/pounds/euros or whatever.
--
Clive Page
Dept of Physics & Astronomy,
University of Leicester,
Leicester, LE1 7RH, U.K.
On 4/5/06, Clive Page <cgp@star.le.ac.uk> wrote: > Since I discovered the facilities in Postgres for providing and listing > column descrptions, I have found them very useful, especially for adding a > string showing physical units to my columns. Have you considered using domains for these types? You can comment the domain appropriately. While the domain description will not show in \d+. to get the description you can do \dT on the domain. Based on your background I also think you might appreciate domains from a design perspective. There are a couple of disadvantages to using them so I'd suggest reading about them. merlin
On Wed, 5 Apr 2006, Merlin Moncure wrote: > Have you considered using domains for these types? You can comment > the domain appropriately. While the domain description will not show > in \d+. to get the description you can do \dT on the domain. > > Based on your background I also think you might appreciate domains > from a design perspective. There are a couple of disadvantages to > using them so I'd suggest reading about them. Thanks for the suggestion, I'll start reading up on them. -- Clive Page Dept of Physics & Astronomy, University of Leicester, Leicester, LE1 7RH, U.K.
On Apr 5, 2006, at 12:15 PM, Merlin Moncure wrote: > On 4/5/06, Clive Page <cgp@star.le.ac.uk> wrote: >> Since I discovered the facilities in Postgres for providing and >> listing >> column descrptions, I have found them very useful, especially for >> adding a >> string showing physical units to my columns. > > Have you considered using domains for these types? You can comment > the domain appropriately. While the domain description will not show > in \d+. to get the description you can do \dT on the domain. > > Based on your background I also think you might appreciate domains > from a design perspective. There are a couple of disadvantages to > using them so I'd suggest reading about them. I seem to recall some astronomer having created some custom types for storing astronomical data in PostgreSQL. Or perhaps he was using PostGIS. I know that other astronomers are using PostgreSQL/PostGIS so if you look around you might be able to save yourself quite a bit of work. -- Jim C. Nasby, Sr. Engineering Consultant jnasby@pervasive.com Pervasive Software http://pervasive.com work: 512-231-6117 vcard: http://jim.nasby.net/pervasive.vcf cell: 512-569-9461
On Thu, 6 Apr 2006, Jim Nasby wrote: > I seem to recall some astronomer having created some custom types for storing > astronomical data in PostgreSQL. Or perhaps he was using PostGIS. I know that > other astronomers are using PostgreSQL/PostGIS so if you look around you > might be able to save yourself quite a bit of work. Well I know about pgAstro and pgSphere (and helped a little in testing them) but maybe there are others. Will look, thanks. -- Clive Page Dept of Physics & Astronomy, University of Leicester, Leicester, LE1 7RH, U.K.