Обсуждение: "COPY FROM" recognize \xDD sequence - addition to copy.c & idea 4 developers

Right now we assume \XXX is octal.  We could support \x as hex because
\x isn't any special backslash character.  However, no one has ever
asked for this.  Does anyone else think this would be benficial?

---------------------------------------------------------------------------

Igor Georgiev wrote:
> 1. Why i do this:
>     I try to migrate a database with a 200 tables from Sybase SQL Anywhere to PostgreSQL,
>     but SQL Anywhere escapes special characters like a HEX values ( like \x0D \x2C ..... ).
>     PostgreSQL COPY FROM recognize only OCT values ( lie \001 ... )
> 2. How-to it' easy :)))
>     2.1 -   Open $UrSourceDir/src/backend/commands/copy.c    
>     2.2 -   Add #include <ctype.h> in te begining
>     2.3  find function    
>         static char *
>         CopyReadAttribute(FILE *fp, bool *isnull, char *delim, int *newline, char *null_print)
>         /*----------------*/
>         /*-------- Add this code before it --------*/
>         static int 
>         HEXVALUE( int c )
>         {
>             if (isdigit(c))
>             {
>                 c -= '0';
>             }
>             else
>             {
>                 if (islower(c))
>                     c= c-'a'+10;
>                 else
>                     c= c-'A'+10;
>             }
>             return(c);
>         }
>     2.4 in body of CopyReadAttribute 
>         find this code and modify it like this
>     if (c == '\\')
>     {
>         c = CopyGetChar(fp);
>         if (c == EOF)
>         goto endOfFile;
>         switch (c)
>             {
>             /*------ Here is my additional code ------*/
>             case 'x':
>             case 'X':
>                 {
>                 int val;
>                 CopyDonePeek(fp, c, true /*pick up*/); /* Get x always */
>                 c = CopyPeekChar(fp); /* Get next */
>                 if (isxdigit(c))
>                 {
>                     val = HEXVALUE(c);
>                     c = CopyPeekChar(fp);
>                     if (isxdigit(c))
>                     {
>                         val = (val << 4) + HEXVALUE(c);
>                         CopyDonePeek(fp, c, true /*pick up*/);
>                     }
>                     else
>                     {
>                     if (c == EOF)
>                         goto endOfFile;
>                         CopyDonePeek(fp, c, false /*put back*/);
>                     }
>                 }
>                 else
>                 {
>                     if (c == EOF)
>                         goto endOfFile;
>                     CopyDonePeek(fp, c, false /*put back*/);
>                 }
>                 c = val;
>             }
>         break;
>         /*------ End of my additional code ------*/
>         case '0':
>         case '1':
>         case '2':
>         case '3':
>         case '4':
>         case '5':
>         case '6':
>         case '7':
>                 {
>                 int val;
>                 val = OCTVALUE(c);
>     2.4 he he now make , make install ....
> 3. An idea to developers : maybe u include this addition to COPY in future releases
>     10x
> 
> P.S. Excuse me for my English ( i'm better in C :)

--  Bruce Momjian                        |  http://candle.pha.pa.us pgman@candle.pha.pa.us               |  (610)
359-1001+  If your life is a hard drive,     |  13 Roberts Road +  Christ can be your backup.        |  Newtown Square,
Pennsylvania19073
 

Bruce Momjian <pgman@candle.pha.pa.us> writes:
> Right now we assume \XXX is octal.  We could support \x as hex because
> \x isn't any special backslash character.  However, no one has ever
> asked for this.  Does anyone else think this would be benficial?

Well, it seems pretty localized and harmless.  If it lets us import
Sybase dumps, doesn't that boost our plans for world domination? ;-)
        regards, tom lane

Tom Lane wrote:
> Bruce Momjian <pgman@candle.pha.pa.us> writes:
> > Right now we assume \XXX is octal.  We could support \x as hex because
> > \x isn't any special backslash character.  However, no one has ever
> > asked for this.  Does anyone else think this would be benficial?
> 
> Well, it seems pretty localized and harmless.  If it lets us import
> Sybase dumps, doesn't that boost our plans for world domination? ;-)

Yes, it does.  I will add it to TODO:
        o Allow copy to understand \x as hex

--  Bruce Momjian                        |  http://candle.pha.pa.us pgman@candle.pha.pa.us               |  (610)
359-1001+  If your life is a hard drive,     |  13 Roberts Road +  Christ can be your backup.        |  Newtown Square,
Pennsylvania19073
 

On Wed, 16 Oct 2002, Tom Lane wrote:

> Bruce Momjian <pgman@candle.pha.pa.us> writes:
> > Right now we assume \XXX is octal.  We could support \x as hex because
> > \x isn't any special backslash character.  However, no one has ever
> > asked for this.  Does anyone else think this would be benficial?
> 
> Well, it seems pretty localized and harmless.  If it lets us import
> Sybase dumps, doesn't that boost our plans for world domination? ;-)

Can we add:
    o    World Domination

To the TODO list?

Gavin

Gavin Sherry wrote:
> On Wed, 16 Oct 2002, Tom Lane wrote:
> 
> > Bruce Momjian <pgman@candle.pha.pa.us> writes:
> > > Right now we assume \XXX is octal.  We could support \x as hex because
> > > \x isn't any special backslash character.  However, no one has ever
> > > asked for this.  Does anyone else think this would be benficial?
> > 
> > Well, it seems pretty localized and harmless.  If it lets us import
> > Sybase dumps, doesn't that boost our plans for world domination? ;-)
> 
> Can we add:
> 
>         o    World Domination
> 
> To the TODO list?

That's already in there, but in subliminal type.

--  Bruce Momjian                        |  http://candle.pha.pa.us pgman@candle.pha.pa.us               |  (610)
359-1001+  If your life is a hard drive,     |  13 Roberts Road +  Christ can be your backup.        |  Newtown Square,
Pennsylvania19073