Thread: DESC
Not just a pgsql novice, but an SQL novice in general. Is there an equivalent for the SQL command DESC for listing the columns and their various types? (I've played around with Oracle's sqlplus stuff a very little bit and this is command existed there and from I've seen so far, should be an ANSI standard.) I looked through the email archives and didn't see anything. Oh, dear. I just went to check again, and off of the User's Lounge, the General Information link (http://www.postgresql.org/gen-info.html) just gave me a 404 error. Someone reorganizing? Anyway, I've pondered writing such a thing, and decided to look at how pg_dump figures things out and quickly decided to ask first. Thanks, mrc -- Mike Castle Life is like a clock: You can work constantly dalgoda@ix.netcom.com and be right all the time, or not work at all www.netcom.com/~dalgoda/ and be right at least twice a day. -- mrc We are all of us living in the shadow of Manhattan. -- Watchmen
Start a psql session on the db you want and type \d <table name> and this will describe the table for you. You should also type \? for more options under psql. Thanks. Rynell Wesson On Tue, 21 Nov 2000, Mike Castle wrote: > > Not just a pgsql novice, but an SQL novice in general. > > Is there an equivalent for the SQL command DESC for listing the columns > and their various types? (I've played around with Oracle's sqlplus stuff > a very little bit and this is command existed there and from I've seen > so far, should be an ANSI standard.) > > I looked through the email archives and didn't see anything. > > Oh, dear. I just went to check again, and off of the User's Lounge, the > General Information link (http://www.postgresql.org/gen-info.html) just > gave me a 404 error. Someone reorganizing? > > Anyway, I've pondered writing such a thing, and decided to look at how > pg_dump figures things out and quickly decided to ask first. > > Thanks, > mrc > -- > Mike Castle Life is like a clock: You can work constantly > dalgoda@ix.netcom.com and be right all the time, or not work at all > www.netcom.com/~dalgoda/ and be right at least twice a day. -- mrc > We are all of us living in the shadow of Manhattan. -- Watchmen >
On Tue, Nov 21, 2000 at 12:58:44PM -0600, Mike Castle wrote: > > Not just a pgsql novice, but an SQL novice in general. > > Is there an equivalent for the SQL command DESC for listing the columns > and their various types? (I've played around with Oracle's sqlplus stuff > a very little bit and this is command existed there and from I've seen > so far, should be an ANSI standard.) > If I understand you correctly, the only thing I know of is available in the psql front end. It is the \d command, as in: \d mytable Else I know of nothing. Unfortunately. Paul
On Tue, Nov 21, 2000 at 08:01:27PM -0500, Paul M Foster wrote: > On Tue, Nov 21, 2000 at 12:58:44PM -0600, Mike Castle wrote: ... > > Is there an equivalent for the SQL command DESC for listing the columns > > and their various types? (I've played around with Oracle's sqlplus stuff > > a very little bit and this is command existed there and from I've seen > > so far, should be an ANSI standard.) ... > If I understand you correctly, the only thing I know of is available in > the psql front end. It is the \d command, as in: > > \d mytable And if you start psql with option -E you will see the actual SQL-queries used by \d. A. -- -------------------------------------------------------------------------- Albert Reiner <areiner@tph.tuwien.ac.at> Deutsch * English * Esperanto * Latine --------------------------------------------------------------------------
On Wed, Nov 22, 2000 at 06:38:15PM +0100, Albert REINER wrote:
> And if you start psql with option -E you will see the actual
> SQL-queries used by \d.
That's nifty. I've read through all of the pgsql documentation before
starting everything, but I think I'm suffering a bit from information
overload. I knew this information was somewhere, I just couldn't remember
where.
So, thanks to all who pointed me to \d.
Ok then. It looks to me like both "DESC" and "DESCRIBE" are SQL keywords.
DESC apparently is meant for descending, so I'm guessing that Oracle's
sqlplus usage of DESC is an extension. Is that correct?
If so, is "DESCRIBE" the ANSI command that should do what \d does or does
it serve another purpose in ANSI? (A pointer as to where to find this
explicitly would be nice; will eventually purchase the standard myself).
If DESCRIBE is supposed to do that, is there any reason that pgsql doesn't
do that outside of "\d works, so no one has bothered to implement it."
Thanks,
mrc
--
Mike Castle Life is like a clock: You can work constantly
dalgoda@ix.netcom.com and be right all the time, or not work at all
www.netcom.com/~dalgoda/ and be right at least twice a day. -- mrc
We are all of us living in the shadow of Manhattan. -- Watchmen
describe isn't really an SQL reserved AFAIK, its used in most "monitor" applications, like sqlplus and pgsql > On Wed, Nov 22, 2000 at 06:38:15PM +0100, Albert REINER wrote: > > And if you start psql with option -E you will see the actual > > SQL-queries used by \d. > > That's nifty. I've read through all of the pgsql documentation before > starting everything, but I think I'm suffering a bit from information > overload. I knew this information was somewhere, I just couldn't remember > where. > > So, thanks to all who pointed me to \d. > > Ok then. It looks to me like both "DESC" and "DESCRIBE" are SQL keywords. > DESC apparently is meant for descending, so I'm guessing that Oracle's > sqlplus usage of DESC is an extension. Is that correct? > > If so, is "DESCRIBE" the ANSI command that should do what \d does or does > it serve another purpose in ANSI? (A pointer as to where to find this > explicitly would be nice; will eventually purchase the standard myself). > > If DESCRIBE is supposed to do that, is there any reason that pgsql doesn't > do that outside of "\d works, so no one has bothered to implement it." > > Thanks, > mrc > -- > Mike Castle Life is like a clock: You can work constantly > dalgoda@ix.netcom.com and be right all the time, or not work at all > www.netcom.com/~dalgoda/ and be right at least twice a day. -- mrc > We are all of us living in the shadow of Manhattan. -- Watchmen > ----------------------------------------------------------------------------- david@backpack.com BackPack Software, Inc. www.backpack.com +1 651.645.7550 voice "Life is an Adventure. +1 651.645.9798 fax Don't forget your BackPack!" -----------------------------------------------------------------------------
Mike Castle <dalgoda@ix.netcom.com> writes:
> If so, is "DESCRIBE" the ANSI command that should do what \d does or does
> it serve another purpose in ANSI?
The only use of DESCRIBE that I can find in the SQL92 spec is
<describe statement> ::=
<describe input statement>
| <describe output statement>
<describe input statement> ::=
DESCRIBE INPUT <SQL statement name> <using descriptor>
<describe output statement> ::=
DESCRIBE [ OUTPUT ] <SQL statement name> <using descriptor>
Obtain information about the <select list> columns or <dynamic
parameter specification>s contained in a prepared statement.
which doesn't appear to overlap \d's functionality at all...
regards, tom lane
On Wed, Nov 22, 2000 at 01:01:10PM -0600, D. Duccini wrote: > > describe isn't really an SQL reserved AFAIK, its used in most "monitor" > applications, like sqlplus and pgsql From http://www.postgresql.org/users-lounge/docs/v7.0/user/syntax.htm The following are either SQL92 or SQL3 reserved key words which are not key words in Postgres. These have no proscribed usage in Postgres at the time of writing (v7.0) but may become reserved key words in the future: [deleted] DATE DEALLOCATE DEC DESCRIBE DESCRIPTOR [deleted] That's why I was asking. More curiosity than anything. mrc -- Mike Castle Life is like a clock: You can work constantly dalgoda@ix.netcom.com and be right all the time, or not work at all www.netcom.com/~dalgoda/ and be right at least twice a day. -- mrc We are all of us living in the shadow of Manhattan. -- Watchmen
See comments below. On Wed, 22 Nov 2000, Mike Castle wrote: > On Wed, Nov 22, 2000 at 06:38:15PM +0100, Albert REINER wrote: > > And if you start psql with option -E you will see the actual > > SQL-queries used by \d. > > That's nifty. I've read through all of the pgsql documentation before > starting everything, but I think I'm suffering a bit from information > overload. I knew this information was somewhere, I just couldn't remember > where. > > So, thanks to all who pointed me to \d. > > Ok then. It looks to me like both "DESC" and "DESCRIBE" are SQL keywords. > DESC apparently is meant for descending, so I'm guessing that Oracle's > sqlplus usage of DESC is an extension. Is that correct? DESC and ASC are SQL keywords used with the ORDER BY keywords for listing values in descending and ascending order, respectively. DESC(RIBE) within an Oracle sqlplus session does not conflict with the SQL DESC keyword. DESC when used within an sqlplus session will display a specified table's definition. One version of DESC is used within SQL DML statements, like SELECT <statement>, and the other is used as a utility within an sqlplus session, just like any utility found within a Unix shell (e.g. ls, find, echo, etc.). > > If so, is "DESCRIBE" the ANSI command that should do what \d does or does > it serve another purpose in ANSI? (A pointer as to where to find this > explicitly would be nice; will eventually purchase the standard myself). > This version of DESCRIBE is for use within embedded SQL programs (C/C++). More specifically, it is used with dynamic SQL select statements within embedded SQL programs and it must be used after the dynamic SQL statement has been compiled using the PREPARE statement. > If DESCRIBE is supposed to do that, is there any reason that pgsql doesn't > do that outside of "\d works, so no one has bothered to implement it." > I haven't written any embedded SQL programs using the traditional EXEC SQL formats (I usually use libpq/libpq++ or JDBC) within PostgreSQL, but PostgreSQL should be able to handle the DESCRIBE statement within embedded SQL programs if it adhered to the embedded SQL specfications for C utilizing EXEC SQL syntax. I hope that I interpreted your questions correctly and I haven't stated too much or too little in answering them and that all of this will give you a better understanding. Thanks. Rynell Wesson