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Fix up foreign-key mechanism so that there is a sound semantic basis for the

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equality checks it applies, instead of a random dependence on whatever
operators might be named "=".  The equality operators will now be selected
from the opfamily of the unique index that the FK constraint depends on to
enforce uniqueness of the referenced columns; therefore they are certain to be
consistent with that index's notion of equality.  Among other things this
should fix the problem noted awhile back that pg_dump may fail for foreign-key
constraints on user-defined types when the required operators aren't in the
search path.  This also means that the former warning condition about "foreign
key constraint will require costly sequential scans" is gone: if the
comparison condition isn't indexable then we'll reject the constraint
entirely. All per past discussions.

Along the way, make the RI triggers look into pg_constraint for their
information, instead of using pg_trigger.tgargs; and get rid of the always
error-prone fixed-size string buffers in ri_triggers.c in favor of building up
the RI queries in StringInfo buffers.

initdb forced due to columns added to pg_constraint and pg_trigger.
This commit is contained in:
Tom Lane
2007-02-14 01:58:58 +00:00
parent 65e2f55031
commit 7bddca3450
33 changed files with 1731 additions and 1665 deletions
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36
src/include/commands/trigger.h
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@ -6,7 +6,7 @@
* Portions Copyright (c) 1996-2007, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
* $PostgreSQL: pgsql/src/include/commands/trigger.h,v 1.60 2007/01/05 22:19:54 momjian Exp $
* $PostgreSQL: pgsql/src/include/commands/trigger.h,v 1.61 2007/02/14 01:58:58 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -78,34 +78,8 @@ typedef struct TriggerData
#define TRIGGER_FIRED_AFTER(event) \
(!TRIGGER_FIRED_BEFORE (event))
/*
* RI trigger function arguments are stored in pg_trigger.tgargs bytea
*
* constrname\0fkrel\0pkrel\0matchtype\0fkatt\0pkatt\0fkatt\0pkatt\0...
*
* There are one or more pairs of fkatt/pkatt names.
*
* The relation names are no longer of much use since they are not
* guaranteed unique; they are present only for backwards compatibility.
* Use the tgrelid and tgconstrrelid fields to identify the referenced
* relations, instead. (But note that which is which will depend on which
* trigger you are looking at!)
*/
#define RI_CONSTRAINT_NAME_ARGNO 0
#define RI_FK_RELNAME_ARGNO 1
#define RI_PK_RELNAME_ARGNO 2
#define RI_MATCH_TYPE_ARGNO 3
#define RI_FIRST_ATTNAME_ARGNO 4 /* first attname pair starts
* here */
#define RI_KEYPAIR_FK_IDX 0
#define RI_KEYPAIR_PK_IDX 1
#define RI_MAX_NUMKEYS INDEX_MAX_KEYS
#define RI_MAX_ARGUMENTS (RI_FIRST_ATTNAME_ARGNO + (RI_MAX_NUMKEYS * 2))
extern Oid CreateTrigger(CreateTrigStmt *stmt, bool forConstraint);
extern Oid CreateTrigger(CreateTrigStmt *stmt, Oid constraintOid);
extern void DropTrigger(Oid relid, const char *trigname,
DropBehavior behavior, bool missing_ok);
@ -175,10 +149,10 @@ extern bool RI_FKey_keyequal_upd_pk(Trigger *trigger, Relation pk_rel,
HeapTuple old_row, HeapTuple new_row);
extern bool RI_FKey_keyequal_upd_fk(Trigger *trigger, Relation fk_rel,
HeapTuple old_row, HeapTuple new_row);
extern bool RI_Initial_Check(FkConstraint *fkconstraint,
Relation rel,
Relation pkrel);
extern bool RI_Initial_Check(Trigger *trigger,
Relation fk_rel, Relation pk_rel);
/* result values for RI_FKey_trigger_type: */
#define RI_TRIGGER_PK 1 /* is a trigger on the PK relation */
#define RI_TRIGGER_FK 2 /* is a trigger on the FK relation */
#define RI_TRIGGER_NONE 0 /* is not an RI trigger function */