Re: [HACKERS] convert int to bytea
Hi Gregory On Thu, 29 Nov 2007, Gregory Stark wrote: Date: Thu, 29 Nov 2007 14:34:57 + From: Gregory Stark [EMAIL PROTECTED] To: [EMAIL PROTECTED] Cc: pgsql-hackers list pgsql-hackers@postgresql.org Subject: Re: convert int to bytea [EMAIL PROTECTED] writes: select 124::bytea doesn't work Is there an other way? (preferabily simple :) This kind of question would be more appropriate on pgsql-general. I know, I should subscribe :) What do you want the resulting bytea to look like? example : id = 9 , bytea = '\000\000\011' IIRC -- Olivier PRENANT Tel: +33-5-61-50-97-00 (Work) 15, Chemin des Monges+33-5-61-50-97-01 (Fax) 31190 AUTERIVE +33-6-07-63-80-64 (GSM) FRANCE Email: [EMAIL PROTECTED] -- Make your life a dream, make your dream a reality. (St Exupery) ---(end of broadcast)--- TIP 5: don't forget to increase your free space map settings
Re: [HACKERS] convert int to bytea
[EMAIL PROTECTED] writes: select 124::bytea doesn't work Is there an other way? (preferabily simple :) This kind of question would be more appropriate on pgsql-general. What do you want the resulting bytea to look like? -- Gregory Stark EnterpriseDB http://www.enterprisedb.com Get trained by Bruce Momjian - ask me about EnterpriseDB's PostgreSQL training! ---(end of broadcast)--- TIP 6: explain analyze is your friend
Re: [HACKERS] convert int to bytea
On 11/29/07, [EMAIL PROTECTED] [EMAIL PROTECTED] wrote: On Thu, 29 Nov 2007, Gregory Stark wrote: What do you want the resulting bytea to look like? example : id = 9 , bytea = '\000\000\011' IIRC What do you expect to happen when server and client are differently-endian? -Doug ---(end of broadcast)--- TIP 3: Have you checked our extensive FAQ? http://www.postgresql.org/docs/faq
Re: [HACKERS] convert int to bytea
Does it matter if you have written an explicit cast for int to bytea? On Nov 29, 2007 9:00 PM, Douglas McNaught [EMAIL PROTECTED] wrote: On 11/29/07, [EMAIL PROTECTED] [EMAIL PROTECTED] wrote: On Thu, 29 Nov 2007, Gregory Stark wrote: What do you want the resulting bytea to look like? example : id = 9 , bytea = '\000\000\011' IIRC What do you expect to happen when server and client are differently-endian? -Doug ---(end of broadcast)--- TIP 3: Have you checked our extensive FAQ? http://www.postgresql.org/docs/faq -- Usama Munir Dar http://linkedin.com/in/usamadar Consultant Architect Cell:+92 321 5020666 Skype: usamadar
Re: [HACKERS] convert int to bytea
Hi, please don't top post to someone who didn't used this convention in answering you. It's impolite. I edited the mail a bit to return sanity. On Nov 29, 2007 9:00 PM, Douglas McNaught [EMAIL PROTECTED] mailto:[EMAIL PROTECTED] wrote: On 11/29/07, [EMAIL PROTECTED] mailto:[EMAIL PROTECTED] [EMAIL PROTECTED] mailto:[EMAIL PROTECTED] wrote: On Thu, 29 Nov 2007, Gregory Stark wrote: What do you want the resulting bytea to look like? example : id = 9 , bytea = '\000\000\011' IIRC What do you expect to happen when server and client are differently-endian? -Doug Usama Dar írta: Does it matter if you have written an explicit cast for int to bytea? You don't know what't endianness is, do you? Say, you have a number: 0x12345678. This is stored differently depending on the endianness. Big-endian (like Sparc, Motorola, etc): 0x12 0x34 0x56 0x78 Little-endian (Intel-compatibles, etc): 0x78 0x56 0x34 0x12 So, how do you want your number to come out as a byte array? Since a bytea is a sequence of bytes as stored in memory, you may have different meaning for an int-bytea conversion. It's your homework to look up what's network order is. :-) But it would give you consistent answer no matter what CPU your server uses. -- -- Zoltán Böszörményi Cybertec Schönig Schönig GmbH http://www.postgresql.at/ ---(end of broadcast)--- TIP 4: Have you searched our list archives? http://archives.postgresql.org
Re: [HACKERS] convert int to bytea
On Nov 29, 2007 9:35 PM, Zoltan Boszormenyi [EMAIL PROTECTED] wrote: Hi, please don't top post to someone who didn't used this convention in answering you. It's impolite. I edited the mail a bit to return sanity. On Nov 29, 2007 9:00 PM, Douglas McNaught [EMAIL PROTECTED] mailto:[EMAIL PROTECTED] wrote: On 11/29/07, [EMAIL PROTECTED] mailto:[EMAIL PROTECTED] [EMAIL PROTECTED] mailto:[EMAIL PROTECTED] wrote: On Thu, 29 Nov 2007, Gregory Stark wrote: What do you want the resulting bytea to look like? example : id = 9 , bytea = '\000\000\011' IIRC What do you expect to happen when server and client are differently-endian? -Doug Usama Dar írta: Does it matter if you have written an explicit cast for int to bytea? You don't know what't endianness is, do you? Say, you have a number: 0x12345678. This is stored differently depending on the endianness. Big-endian (like Sparc, Motorola, etc): 0x12 0x34 0x56 0x78 Little-endian (Intel-compatibles, etc): 0x78 0x56 0x34 0x12 So, how do you want your number to come out as a byte array? Since a bytea is a sequence of bytes as stored in memory, you may have different meaning for an int-bytea conversion. It's your homework to look up what's network order is. :-) But it would give you consistent answer no matter what CPU your server uses. 1) i wasn't aware people are sensitive to top email reply vs inline, apologies if it offended you 2) i know what a byte order is , i just thought your interface i.e. libpq would convert it to the local byte order. -- -- Zoltán Böszörményi Cybertec Schönig Schönig GmbH http://www.postgresql.at/ -- Usama Munir Dar http://linkedin.com/in/usamadar Consultant Architect Cell:+92 321 5020666 Skype: usamadar
Re: [HACKERS] convert int to bytea
Usama Dar wrote: 2) i know what a byte order is , i just thought your interface i.e. libpq would convert it to the local byte order. You haven't thought this through. Data traveling over libpq is still text, not binary, in most cases, so byte order is irrelevant at that time. The translation to a bytea (if possible) would be done after the data was already on the server and the int was in its native, architecture dependent form. The short answer is thus still that there is no sane consistent cast from int to bytea. If you want a bytea then it's really up to you to contruct the byte array. cheers andrew ---(end of broadcast)--- TIP 2: Don't 'kill -9' the postmaster
