Thread: Desc Commnad in pgsql?
<div class="gmail_quote"><br /><br />Hello All,<br /><br />I like to know how can I achieve the same functionality that isgive by desc commnad in mysql or oracle.<br />Also specify me the book related to pgsql as a beginner.<br />Presently mytask is going to be communication of ruby with pgsql<br /><br />Thanks in advanced.<br /><br />Vikas<br /></div><br />
am Thu, dem 17.04.2008, um 14:17:45 +0530 mailte VG folgendes: > > > Hello All, > > I like to know how can I achieve the same functionality that is give by desc > commnad in mysql or oracle. 'desc'? descending, describe, desc... wild guess: describe, like ORA. You can use \d within psql, please read the welcome-message. Andreas -- Andreas Kretschmer Kontakt: Heynitz: 035242/47150, D1: 0160/7141639 (mehr: -> Header) GnuPG-ID: 0x3FFF606C, privat 0x7F4584DA http://wwwkeys.de.pgp.net
VG wrote: > Hello All, > > I like to know how can I achieve the same functionality that is give by desc > commnad in mysql or oracle. http://www.postgresql.org/docs/8.3/static/app-psql.html See the \d command, e.g. "\d mytable" There are many different backslash commands that can give you details on tables, views, functions, schemas etc. > Also specify me the book related to pgsql as a beginner. http://www.postgresql.org/docs/8.3/static/index.html http://www.postgresql.org/docs/books/ > Presently my task is going to be communication of ruby with pgsql Start here I suppose: http://rubyforge.org/projects/ruby-pg/ -- Richard Huxton Archonet Ltd
The world rejoiced as vikasraigupta@gmail.com (VG) wrote:
> Hello All,
> I like to know how can I achieve the same functionality that is give by desc commnad in mysql or oracle.
> Also specify me the book related to pgsql as a beginner.
> Presently my task is going to be communication of ruby with pgsql
> Thanks in advanced.
If you were referring to the usage of "desc" to indicate "descending
order", as in: select * from some table order by id desc
well, that's pretty standard SQL usage, and will work much as it
would in MySQL(tm) or Oracle.
If you're looking for ways to "describe" a table, there are two
mechanisms:
1. SQL standard (probably SQL:1993) describes an "information_schema" which contains tables or views that allow
queryingdatabase metadata in a fairly standard fashion.
PostgreSQL supports that.
2. Probably easier and friendlier, albeit nonportable, is to use the psql "\d" command.
Here's an example:
cbbrowne@wolfe:~> psql ledgersmb
Saturday 12:51:13
Welcome to psql 8.1.10, the PostgreSQL interactive terminal.
Type: \copyright for distribution terms \h for help with SQL commands \? for help with psql commands \g
orterminate with semicolon to execute query \q to quit
ledgersmb=# \d acc_trans Table "public.acc_trans" Column | Type |
Modifiers
----------------+---------+-------------------------------------------------------------trans_id | integer |
chart_id | integer | not nulltransdate | date | default date('now'::text)source | text |
cleared | boolean | default falsefx_transaction | boolean | default falseproject_id | integer | memo
| text | invoice_id | integer | amount | numeric | entry_id | bigint | not null default
nextval('acctrans_entry_id_seq'::regclass)
Indexes: "acc_trans_pkey" PRIMARY KEY, btree (entry_id) "acc_trans_chart_id_key" btree (chart_id)
"acc_trans_source_key"btree (lower(source)) "acc_trans_trans_id_key" btree (trans_id) "acc_trans_transdate_key"
btree(transdate)
Foreign-key constraints: "$1" FOREIGN KEY (chart_id) REFERENCES chart(id) "$2" FOREIGN KEY (chart_id) REFERENCES
chart(id) "$3" FOREIGN KEY (chart_id) REFERENCES chart(id) "$4" FOREIGN KEY (chart_id) REFERENCES chart(id)
"acc_trans_chart_id_fkey"FOREIGN KEY (chart_id) REFERENCES chart(id)
You can query the schemas for all sorts of objects, complete with
tab-completion; type "\?" at the psql prompt to see all of the
internal psql commands. There is a whole section entitled
"Informational" that shows modifiers to \d to query various sorts of
objects.
For instance:
\dt will list all tables
\ds will list all sequences
\dv will list all views
and there's a further cast of ~20 variants for various different sorts
of objects.
--
let name="cbbrowne" and tld="gmail.com" in String.concat "@" [name;tld];;
http://linuxdatabases.info/info/postgresql.html
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I like the table and other info from psql and find I sometimes need that info in my client programs. Are there any SQL/plpgsql functions that are analogous to the psql \dt, \ds, etc. commands? For example create function d_table(table_name text) returns setof record that could be used in SQL commands in client programs? I am not concerned whether these are compatible with other RDBMS. TJ O'Donnell http://www.gnova.com > > If you're looking for ways to "describe" a table, there are two > mechanisms: > > 1. SQL standard (probably SQL:1993) describes an > "information_schema" which contains tables or views that allow > querying database metadata in a fairly standard fashion. > > PostgreSQL supports that. > > 2. Probably easier and friendlier, albeit nonportable, is to use > the psql "\d" command. > > >> >> For instance: >> \dt will list all tables >> \ds will list all sequences >> \dv will list all views >> and there's a further cast of ~20 variants for various different sorts >> of objects.
TJ O'Donnell wrote: > I like the table and other info from psql > and find I sometimes need that info in my client programs. > Are there any SQL/plpgsql functions that are analogous > to the psql \dt, \ds, etc. commands? If you start psql with the -E option it will show you the queries it used to build the response tables. -- Alvaro Herrera http://www.CommandPrompt.com/ PostgreSQL Replication, Consulting, Custom Development, 24x7 support