diff options
Diffstat (limited to 'src/include/access/skey.h')
| -rw-r--r-- | src/include/access/skey.h | 9 |
1 files changed, 8 insertions, 1 deletions
diff --git a/src/include/access/skey.h b/src/include/access/skey.h index fc86d37041c..c2ac060250c 100644 --- a/src/include/access/skey.h +++ b/src/include/access/skey.h @@ -7,7 +7,7 @@ * Portions Copyright (c) 1996-2007, PostgreSQL Global Development Group * Portions Copyright (c) 1994, Regents of the University of California * - * $PostgreSQL: pgsql/src/include/access/skey.h,v 1.34 2007/01/05 22:19:51 momjian Exp $ + * $PostgreSQL: pgsql/src/include/access/skey.h,v 1.35 2007/04/06 22:33:42 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -52,6 +52,12 @@ typedef uint16 StrategyNumber; * the operator. When using a ScanKey in a heap scan, these fields are not * used and may be set to InvalidStrategy/InvalidOid. * + * A ScanKey can also represent a condition "column IS NULL"; this is signaled + * by the SK_SEARCHNULL flag bit. In this case the argument is always NULL, + * and the sk_strategy, sk_subtype, and sk_func fields are not used (unless + * set by the index AM). Currently, SK_SEARCHNULL is supported only for + * index scans, not heap scans; and not all index AMs support it. + * * Note: in some places, ScanKeys are used as a convenient representation * for the invocation of an access method support procedure. In this case * sk_strategy/sk_subtype are not meaningful, and sk_func may refer to a @@ -111,6 +117,7 @@ typedef ScanKeyData *ScanKey; #define SK_ROW_HEADER 0x0004 /* row comparison header (see above) */ #define SK_ROW_MEMBER 0x0008 /* row comparison member (see above) */ #define SK_ROW_END 0x0010 /* last row comparison member (see above) */ +#define SK_SEARCHNULL 0x0020 /* scankey represents a "col IS NULL" qual */ /* |