diff --git a/src/backend/utils/adt/ri_triggers.c b/src/backend/utils/adt/ri_triggers.c
index f1fe5fa7f68e27e64c73cd25803619dbe21b76cb..5de6816a49abaa8aa6575bc44dd67cef914e5342 100644
--- a/src/backend/utils/adt/ri_triggers.c
+++ b/src/backend/utils/adt/ri_triggers.c
@@ -309,14 +309,13 @@ RI_FKey_check(PG_FUNCTION_ARGS)
pk_rel = heap_open(riinfo.pk_relid, RowShareLock);
/* ----------
- * SQL3 11.9 <referential constraint definition>
- * General rules 2) a):
+ * SQL:2008 4.17.3 <Table constraints>
* If Rf and Rt are empty (no columns to compare given)
* constraint is true if 0 < (SELECT COUNT(*) FROM T)
*
* Note: The special case that no columns are given cannot
- * occur up to now in Postgres, it's just there for
- * future enhancements.
+ * occur at present in Postgres (and is disallowed by the
+ * standard too); it's just there for future enhancements.
* ----------
*/
if (riinfo.nkeys == 0)
@@ -376,10 +375,8 @@ RI_FKey_check(PG_FUNCTION_ARGS)
case RI_KEYS_ALL_NULL:
/*
- * No check - if NULLs are allowed at all is already checked by
- * NOT NULL constraint.
- *
- * This is true for MATCH FULL, MATCH PARTIAL, and MATCH SIMPLE.
+ * No further check needed - an all-NULL key passes every type of
+ * foreign key constraint.
*/
heap_close(pk_rel, RowShareLock);
return PointerGetDatum(NULL);
@@ -410,7 +407,8 @@ RI_FKey_check(PG_FUNCTION_ARGS)
case FKCONSTR_MATCH_SIMPLE:
/*
- * MATCH SIMPLE - if ANY column is null, we have a match.
+ * MATCH SIMPLE - if ANY column is null, the key passes
+ * the constraint.
*/
heap_close(pk_rel, RowShareLock);
return PointerGetDatum(NULL);
@@ -578,8 +576,8 @@ ri_Check_Pk_Match(Relation pk_rel, Relation fk_rel,
case FKCONSTR_MATCH_SIMPLE:
/*
- * MATCH SIMPLE/FULL - if ANY column is null, we
- * can't be matching to this row already.
+ * MATCH SIMPLE/FULL - if ANY column is null, nothing
+ * could have been referencing this row.
*/
return true;
@@ -734,10 +732,10 @@ RI_FKey_noaction_del(PG_FUNCTION_ARGS)
switch (riinfo.confmatchtype)
{
/* ----------
- * SQL3 11.9 <referential constraint definition>
- * General rules 6) a) iv):
+ * SQL:2008 15.17 <Execution of referential actions>
+ * General rules 9) a) iv):
* MATCH SIMPLE/FULL
- * ... ON DELETE CASCADE
+ * ... ON DELETE NO ACTION
* ----------
*/
case FKCONSTR_MATCH_SIMPLE:
@@ -751,8 +749,8 @@ RI_FKey_noaction_del(PG_FUNCTION_ARGS)
case RI_KEYS_SOME_NULL:
/*
- * No check - MATCH FULL means there cannot be any
- * reference to old key if it contains NULL
+ * No check needed - there cannot be any reference to old
+ * key if it contains a NULL
*/
heap_close(fk_rel, RowShareLock);
return PointerGetDatum(NULL);
@@ -905,10 +903,10 @@ RI_FKey_noaction_upd(PG_FUNCTION_ARGS)
switch (riinfo.confmatchtype)
{
/* ----------
- * SQL3 11.9 <referential constraint definition>
- * General rules 6) a) iv):
+ * SQL:2008 15.17 <Execution of referential actions>
+ * General rules 10) a) iv):
* MATCH SIMPLE/FULL
- * ... ON DELETE CASCADE
+ * ... ON UPDATE NO ACTION
* ----------
*/
case FKCONSTR_MATCH_SIMPLE:
@@ -922,8 +920,8 @@ RI_FKey_noaction_upd(PG_FUNCTION_ARGS)
case RI_KEYS_SOME_NULL:
/*
- * No check - MATCH FULL means there cannot be any
- * reference to old key if it contains NULL
+ * No check needed - there cannot be any reference to old
+ * key if it contains a NULL
*/
heap_close(fk_rel, RowShareLock);
return PointerGetDatum(NULL);
@@ -1090,8 +1088,8 @@ RI_FKey_cascade_del(PG_FUNCTION_ARGS)
switch (riinfo.confmatchtype)
{
/* ----------
- * SQL3 11.9 <referential constraint definition>
- * General rules 6) a) i):
+ * SQL:2008 15.17 <Execution of referential actions>
+ * General rules 9) a) i):
* MATCH SIMPLE/FULL
* ... ON DELETE CASCADE
* ----------
@@ -1107,8 +1105,8 @@ RI_FKey_cascade_del(PG_FUNCTION_ARGS)
case RI_KEYS_SOME_NULL:
/*
- * No check - MATCH FULL means there cannot be any
- * reference to old key if it contains NULL
+ * No check needed - there cannot be any reference to old
+ * key if it contains a NULL
*/
heap_close(fk_rel, RowExclusiveLock);
return PointerGetDatum(NULL);
@@ -1209,7 +1207,7 @@ RI_FKey_cascade_del(PG_FUNCTION_ARGS)
/* ----------
* RI_FKey_cascade_upd -
*
- * Cascaded update/delete foreign key references at update event on PK table.
+ * Cascaded update foreign key references at update event on PK table.
* ----------
*/
Datum
@@ -1258,8 +1256,8 @@ RI_FKey_cascade_upd(PG_FUNCTION_ARGS)
switch (riinfo.confmatchtype)
{
/* ----------
- * SQL3 11.9 <referential constraint definition>
- * General rules 7) a) i):
+ * SQL:2008 15.17 <Execution of referential actions>
+ * General rules 10) a) i):
* MATCH SIMPLE/FULL
* ... ON UPDATE CASCADE
* ----------
@@ -1275,8 +1273,8 @@ RI_FKey_cascade_upd(PG_FUNCTION_ARGS)
case RI_KEYS_SOME_NULL:
/*
- * No update - MATCH FULL means there cannot be any
- * reference to old key if it contains NULL
+ * No check needed - there cannot be any reference to old
+ * key if it contains a NULL
*/
heap_close(fk_rel, RowExclusiveLock);
return PointerGetDatum(NULL);
@@ -1401,12 +1399,10 @@ RI_FKey_cascade_upd(PG_FUNCTION_ARGS)
*
* Restrict delete from PK table to rows unreferenced by foreign key.
*
- * SQL3 intends that this referential action occur BEFORE the
- * update is performed, rather than after. This appears to be
- * the only difference between "NO ACTION" and "RESTRICT".
- *
- * For now, however, we treat "RESTRICT" and "NO ACTION" as
- * equivalent.
+ * The SQL standard intends that this referential action occur BEFORE
+ * the delete is performed, rather than after. This appears to be
+ * the only difference between "NO ACTION" and "RESTRICT". In Postgres
+ * we still implement this as an AFTER trigger, but it's non-deferrable.
* ----------
*/
Datum
@@ -1451,10 +1447,10 @@ RI_FKey_restrict_del(PG_FUNCTION_ARGS)
switch (riinfo.confmatchtype)
{
/* ----------
- * SQL3 11.9 <referential constraint definition>
- * General rules 6) a) iv):
+ * SQL:2008 15.17 <Execution of referential actions>
+ * General rules 9) a) iv):
* MATCH SIMPLE/FULL
- * ... ON DELETE CASCADE
+ * ... ON DELETE RESTRICT
* ----------
*/
case FKCONSTR_MATCH_SIMPLE:
@@ -1468,8 +1464,8 @@ RI_FKey_restrict_del(PG_FUNCTION_ARGS)
case RI_KEYS_SOME_NULL:
/*
- * No check - MATCH FULL means there cannot be any
- * reference to old key if it contains NULL
+ * No check needed - there cannot be any reference to old
+ * key if it contains a NULL
*/
heap_close(fk_rel, RowShareLock);
return PointerGetDatum(NULL);
@@ -1574,12 +1570,10 @@ RI_FKey_restrict_del(PG_FUNCTION_ARGS)
*
* Restrict update of PK to rows unreferenced by foreign key.
*
- * SQL3 intends that this referential action occur BEFORE the
- * update is performed, rather than after. This appears to be
- * the only difference between "NO ACTION" and "RESTRICT".
- *
- * For now, however, we treat "RESTRICT" and "NO ACTION" as
- * equivalent.
+ * The SQL standard intends that this referential action occur BEFORE
+ * the update is performed, rather than after. This appears to be
+ * the only difference between "NO ACTION" and "RESTRICT". In Postgres
+ * we still implement this as an AFTER trigger, but it's non-deferrable.
* ----------
*/
Datum
@@ -1627,10 +1621,10 @@ RI_FKey_restrict_upd(PG_FUNCTION_ARGS)
switch (riinfo.confmatchtype)
{
/* ----------
- * SQL3 11.9 <referential constraint definition>
- * General rules 6) a) iv):
+ * SQL:2008 15.17 <Execution of referential actions>
+ * General rules 10) a) iv):
* MATCH SIMPLE/FULL
- * ... ON DELETE CASCADE
+ * ... ON UPDATE RESTRICT
* ----------
*/
case FKCONSTR_MATCH_SIMPLE:
@@ -1644,8 +1638,8 @@ RI_FKey_restrict_upd(PG_FUNCTION_ARGS)
case RI_KEYS_SOME_NULL:
/*
- * No check - MATCH FULL means there cannot be any
- * reference to old key if it contains NULL
+ * No check needed - there cannot be any reference to old
+ * key if it contains a NULL
*/
heap_close(fk_rel, RowShareLock);
return PointerGetDatum(NULL);
@@ -1802,8 +1796,8 @@ RI_FKey_setnull_del(PG_FUNCTION_ARGS)
switch (riinfo.confmatchtype)
{
/* ----------
- * SQL3 11.9 <referential constraint definition>
- * General rules 6) a) ii):
+ * SQL:2008 15.17 <Execution of referential actions>
+ * General rules 9) a) ii):
* MATCH SIMPLE/FULL
* ... ON DELETE SET NULL
* ----------
@@ -1819,8 +1813,8 @@ RI_FKey_setnull_del(PG_FUNCTION_ARGS)
case RI_KEYS_SOME_NULL:
/*
- * No update - MATCH FULL means there cannot be any
- * reference to old key if it contains NULL
+ * No check needed - there cannot be any reference to old
+ * key if it contains a NULL
*/
heap_close(fk_rel, RowExclusiveLock);
return PointerGetDatum(NULL);
@@ -1977,8 +1971,8 @@ RI_FKey_setnull_upd(PG_FUNCTION_ARGS)
switch (riinfo.confmatchtype)
{
/* ----------
- * SQL3 11.9 <referential constraint definition>
- * General rules 7) a) ii) 2):
+ * SQL:2008 15.17 <Execution of referential actions>
+ * General rules 10) a) ii):
* MATCH SIMPLE/FULL
* ... ON UPDATE SET NULL
* ----------
@@ -1994,8 +1988,8 @@ RI_FKey_setnull_upd(PG_FUNCTION_ARGS)
case RI_KEYS_SOME_NULL:
/*
- * No update - MATCH FULL means there cannot be any
- * reference to old key if it contains NULL
+ * No check needed - there cannot be any reference to old
+ * key if it contains a NULL
*/
heap_close(fk_rel, RowExclusiveLock);
return PointerGetDatum(NULL);
@@ -2158,8 +2152,8 @@ RI_FKey_setdefault_del(PG_FUNCTION_ARGS)
switch (riinfo.confmatchtype)
{
/* ----------
- * SQL3 11.9 <referential constraint definition>
- * General rules 6) a) iii):
+ * SQL:2008 15.17 <Execution of referential actions>
+ * General rules 9) a) iii):
* MATCH SIMPLE/FULL
* ... ON DELETE SET DEFAULT
* ----------
@@ -2175,8 +2169,8 @@ RI_FKey_setdefault_del(PG_FUNCTION_ARGS)
case RI_KEYS_SOME_NULL:
/*
- * No update - MATCH FULL means there cannot be any
- * reference to old key if it contains NULL
+ * No check needed - there cannot be any reference to old
+ * key if it contains a NULL
*/
heap_close(fk_rel, RowExclusiveLock);
return PointerGetDatum(NULL);
@@ -2344,8 +2338,8 @@ RI_FKey_setdefault_upd(PG_FUNCTION_ARGS)
switch (riinfo.confmatchtype)
{
/* ----------
- * SQL3 11.9 <referential constraint definition>
- * General rules 7) a) iii):
+ * SQL:2008 15.17 <Execution of referential actions>
+ * General rules 10) a) iii):
* MATCH SIMPLE/FULL
* ... ON UPDATE SET DEFAULT
* ----------
@@ -2361,8 +2355,8 @@ RI_FKey_setdefault_upd(PG_FUNCTION_ARGS)
case RI_KEYS_SOME_NULL:
/*
- * No update - MATCH FULL means there cannot be any
- * reference to old key if it contains NULL
+ * No check needed - there cannot be any reference to old
+ * key if it contains a NULL
*/
heap_close(fk_rel, RowExclusiveLock);
return PointerGetDatum(NULL);