Обсуждение: 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.