Re: system catalog relation of a table and a serial sequence

[2001-12-15 21:43] Tom Lane said:
| Brent Verner <brent(at)rcfile(dot)org> writes:
| > 1) Is a strcmp(firststrtok,"nextval('") == 0 sufficient to determine
| > that the adsrc is indeed one that we're looking for? If not,
| > suggestions are greatly appreciated :-)
|
| I would not use strtok at all, but look for nextval('" at the start
| of the string and "'::text) at the end. If both match, and there's
| at least one character between, then the intervening text can be
| presumed to be a sequence name. You might further check that the
| apparent sequence name ends with _seq --- if not, it wasn't generated
| by SERIAL.

Why not use strtok? The following should be safe, no?

t1 = strtok(adsrc,"\"");
t2 = strtok(NULL,"\"");
t3 = strtok(NULL,"\"");

if( t0 && t2
&& strcmp(t0,"nextval('") == 0
&& strcmp(t2,"'::text)") == 0 ){
/* this is a call to nextval, check for t1 =~ /_seq$/ */

}

| > 2) Should this function now look like .. ?
| > char** getSerialSequenceNames(const char* table)
| > Or would you suggest it return a smarter struct?
|
| char** (null-terminated vector) would probably work.
|
| BTW, don't forget you have the OID of the table available from the table
| list, so you can avoid the subselect, as well as the relname quoting
| issues that you didn't take care of. When a tablename argument is
| provided, I'd be inclined to make a pre-pass over the table list to see
| if it matches any non-sequence table names, and if so build a list of
| their associated sequence name(s). Keep in mind that we'll probably
| generalize the tablename argument to support wildcarding someday soon,
| so it'd be good if the code could cope with more than one matching
| table.

gotcha.

thanks.
brent

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