diff options
Diffstat (limited to 'src/backend/utils/adt/ri_triggers.c')
| -rw-r--r-- | src/backend/utils/adt/ri_triggers.c | 130 |
1 files changed, 62 insertions, 68 deletions
diff --git a/src/backend/utils/adt/ri_triggers.c b/src/backend/utils/adt/ri_triggers.c index f1fe5fa7f68..5de6816a49a 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); |