Thread

1. inserting binary in a bytea field

   Olivier Jeannet <jeannet@montrouge.tt.slb.com> — 2000-12-01T18:21:27Z

   ============================================================================
                           POSTGRESQL BUG REPORT TEMPLATE
   ============================================================================
   
   
   Your name		:	Olivier Jeannet
   Your email address	:       ojeannet@slb.com
   
   
   System Configuration
   ---------------------
     Architecture (example: Intel Pentium)  	: Intel Pentium
   
     Operating System (example: Linux 2.0.26 ELF) 	: Linux 2.2.13
   
     PostgreSQL version (example: PostgreSQL-7.0):   PostgreSQL-7.0.2
   
     Compiler used (example:  gcc 2.8.0)		: gcc version egcs-2.91.66
                                                     (egcs-1.1.2 release)
   
   Please enter a FULL description of your problem:
   ------------------------------------------------
   
   There is a bug when inserting binary values (non-ASCII) in a bytea field,
   the escape method ("\\134") doesn't work as expected.
   (maybe it is not a bug)
   
   
   
   Please describe a way to repeat the problem.   Please try to provide a
   concise reproducible example, if at all possible: 
   ----------------------------------------------------------------------
   
   Here is the script :
     CREATE TABLE az( a bytea);
     INSERT INTO az VALUES('\\145');
   The SELECT gives 'e' which is correct as ASCII 'e' = '\145' (0x65) .
   
   Now the problem.
   
   With the following :
     INSERT INTO az VALUES('\\002');
   The SELECT gives the following result : '\002', i.e. four characters,
   and not one byte with value of "2". The length of four has been checked
   using JDBC.
   
   With the following :
     INSERT INTO az VALUES('\\134');
   The SELECT gives the following result : '\\', i.e. a double backslash
   instead of a single one.
   
   Is this normal ?
   Am I supposed to get binary values as escaped ASCII, in order to do a
   "sprintf(myvar, sql_result)" to get the real data in myvar ?
   
   
   If you know how this problem might be fixed, list the solution below:
   ---------------------------------------------------------------------
   
   Not known.
   
   
   
   -- 
   Olivier Jeannet - e-Payment solutions
     I prefer not running 32 bit extensions for a 16 bit patch to an 8 bit
     operating system originally coded for a 4 bit microprocessor, written
     by a 2 bit company, that can't stand 1 bit of competition.
   
   

2. Re: inserting binary in a bytea field

   Tom Lane <tgl@sss.pgh.pa.us> — 2000-12-01T18:38:14Z

   Olivier Jeannet <jeannet@montrouge.tt.slb.com> writes:
   > Is this normal ?
   > Am I supposed to get binary values as escaped ASCII,
   
   Yes.  Otherwise you'd have big trouble with, for example, \000.
   
   You can use a binary cursor to read out unconverted data, but that might
   be more trouble than it's worth.
   
   There has been talk of designing some access functions similar to the
   large-object functionality (lo_read/lo_write, etc) for bytea values.
   That would bypass this issue and also allow reading/writing large
   values in sections, which'd be awfully nice.  Not done yet though.
   
   			regards, tom lane