ri_triggers.c

来自「postgresql8.3.4源码,开源数据库」· C语言 代码 · 共 2,476 行 · 第 1/5 页

	if (SPI_finish() != SPI_OK_FINISH)
		elog(ERROR, "SPI_finish failed");

	heap_close(pk_rel, RowShareLock);

	return PointerGetDatum(NULL);
}


/* ----------
 * RI_FKey_check_ins -
 *
 *	Check foreign key existence at insert event on FK table.
 * ----------
 */
Datum
RI_FKey_check_ins(PG_FUNCTION_ARGS)
{
	return RI_FKey_check(fcinfo);
}


/* ----------
 * RI_FKey_check_upd -
 *
 *	Check foreign key existence at update event on FK table.
 * ----------
 */
Datum
RI_FKey_check_upd(PG_FUNCTION_ARGS)
{
	return RI_FKey_check(fcinfo);
}


/* ----------
 * ri_Check_Pk_Match
 *
 * Check for matching value of old pk row in current state for
 * noaction triggers. Returns false if no row was found and a fk row
 * could potentially be referencing this row, true otherwise.
 * ----------
 */
static bool
ri_Check_Pk_Match(Relation pk_rel, Relation fk_rel,
				  HeapTuple old_row,
				  const RI_ConstraintInfo *riinfo)
{
	SPIPlanPtr	qplan;
	RI_QueryKey qkey;
	int			i;
	bool		result;

	ri_BuildQueryKeyPkCheck(&qkey, riinfo, RI_PLAN_CHECK_LOOKUPPK);

	switch (ri_NullCheck(pk_rel, old_row, &qkey, RI_KEYPAIR_PK_IDX))
	{
		case RI_KEYS_ALL_NULL:

			/*
			 * No check - nothing could have been referencing this row anyway.
			 */
			return true;

		case RI_KEYS_SOME_NULL:

			/*
			 * This is the only case that differs between the three kinds of
			 * MATCH.
			 */
			switch (riinfo->confmatchtype)
			{
				case FKCONSTR_MATCH_FULL:
				case FKCONSTR_MATCH_UNSPECIFIED:

					/*
					 * MATCH <unspecified>/FULL  - if ANY column is null, we
					 * can't be matching to this row already.
					 */
					return true;

				case FKCONSTR_MATCH_PARTIAL:

					/*
					 * MATCH PARTIAL - all non-null columns must match. (not
					 * implemented, can be done by modifying the query below
					 * to only include non-null columns, or by writing a
					 * special version here)
					 */
					ereport(ERROR,
							(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
							 errmsg("MATCH PARTIAL not yet implemented")));
					break;
			}

		case RI_KEYS_NONE_NULL:

			/*
			 * Have a full qualified key - continue below for all three kinds
			 * of MATCH.
			 */
			break;
	}

	if (SPI_connect() != SPI_OK_CONNECT)
		elog(ERROR, "SPI_connect failed");

	/*
	 * Fetch or prepare a saved plan for the real check
	 */
	if ((qplan = ri_FetchPreparedPlan(&qkey)) == NULL)
	{
		StringInfoData querybuf;
		char		pkrelname[MAX_QUOTED_REL_NAME_LEN];
		char		attname[MAX_QUOTED_NAME_LEN];
		char		paramname[16];
		const char *querysep;
		Oid			queryoids[RI_MAX_NUMKEYS];

		/* ----------
		 * The query string built is
		 *	SELECT 1 FROM ONLY <pktable> WHERE pkatt1 = $1 [AND ...] FOR SHARE
		 * The type id's for the $ parameters are those of the
		 * PK attributes themselves.
		 * ----------
		 */
		initStringInfo(&querybuf);
		quoteRelationName(pkrelname, pk_rel);
		appendStringInfo(&querybuf, "SELECT 1 FROM ONLY %s x", pkrelname);
		querysep = "WHERE";
		for (i = 0; i < riinfo->nkeys; i++)
		{
			Oid			pk_type = RIAttType(pk_rel, riinfo->pk_attnums[i]);

			quoteOneName(attname,
						 RIAttName(pk_rel, riinfo->pk_attnums[i]));
			sprintf(paramname, "$%d", i + 1);
			ri_GenerateQual(&querybuf, querysep,
							attname, pk_type,
							riinfo->pp_eq_oprs[i],
							paramname, pk_type);
			querysep = "AND";
			queryoids[i] = pk_type;
		}
		appendStringInfo(&querybuf, " FOR SHARE OF x");

		/* Prepare and save the plan */
		qplan = ri_PlanCheck(querybuf.data, riinfo->nkeys, queryoids,
							 &qkey, fk_rel, pk_rel, true);
	}

	/*
	 * We have a plan now. Run it.
	 */
	result = ri_PerformCheck(&qkey, qplan,
							 fk_rel, pk_rel,
							 old_row, NULL,
							 true,		/* treat like update */
							 SPI_OK_SELECT, NULL);

	if (SPI_finish() != SPI_OK_FINISH)
		elog(ERROR, "SPI_finish failed");

	return result;
}


/* ----------
 * RI_FKey_noaction_del -
 *
 *	Give an error and roll back the current transaction if the
 *	delete has resulted in a violation of the given referential
 *	integrity constraint.
 * ----------
 */
Datum
RI_FKey_noaction_del(PG_FUNCTION_ARGS)
{
	TriggerData *trigdata = (TriggerData *) fcinfo->context;
	RI_ConstraintInfo riinfo;
	Relation	fk_rel;
	Relation	pk_rel;
	HeapTuple	old_row;
	RI_QueryKey qkey;
	SPIPlanPtr	qplan;
	int			i;

	/*
	 * Check that this is a valid trigger call on the right time and event.
	 */
	ri_CheckTrigger(fcinfo, "RI_FKey_noaction_del", RI_TRIGTYPE_DELETE);

	/*
	 * Get arguments.
	 */
	ri_FetchConstraintInfo(&riinfo,
						   trigdata->tg_trigger, trigdata->tg_relation, true);

	/*
	 * Nothing to do if no column names to compare given
	 */
	if (riinfo.nkeys == 0)
		return PointerGetDatum(NULL);

	/*
	 * Get the relation descriptors of the FK and PK tables and the old tuple.
	 *
	 * fk_rel is opened in RowShareLock mode since that's what our eventual
	 * SELECT FOR SHARE will get on it.
	 */
	fk_rel = heap_open(riinfo.fk_relid, RowShareLock);
	pk_rel = trigdata->tg_relation;
	old_row = trigdata->tg_trigtuple;

	if (ri_Check_Pk_Match(pk_rel, fk_rel, old_row, &riinfo))
	{
		/*
		 * There's either another row, or no row could match this one.  In
		 * either case, we don't need to do the check.
		 */
		heap_close(fk_rel, RowShareLock);
		return PointerGetDatum(NULL);
	}

	switch (riinfo.confmatchtype)
	{
			/* ----------
			 * SQL3 11.9 <referential constraint definition>
			 *	Gereral rules 6) a) iv):
			 *		MATCH <unspecified> or MATCH FULL
			 *			... ON DELETE CASCADE
			 * ----------
			 */
		case FKCONSTR_MATCH_UNSPECIFIED:
		case FKCONSTR_MATCH_FULL:
			ri_BuildQueryKeyFull(&qkey, &riinfo,
								 RI_PLAN_NOACTION_DEL_CHECKREF);

			switch (ri_NullCheck(pk_rel, old_row, &qkey, RI_KEYPAIR_PK_IDX))
			{
				case RI_KEYS_ALL_NULL:
				case RI_KEYS_SOME_NULL:

					/*
					 * No check - MATCH FULL means there cannot be any
					 * reference to old key if it contains NULL
					 */
					heap_close(fk_rel, RowShareLock);
					return PointerGetDatum(NULL);

				case RI_KEYS_NONE_NULL:

					/*
					 * Have a full qualified key - continue below
					 */
					break;
			}

			if (SPI_connect() != SPI_OK_CONNECT)
				elog(ERROR, "SPI_connect failed");

			/*
			 * Fetch or prepare a saved plan for the restrict delete lookup if
			 * foreign references exist
			 */
			if ((qplan = ri_FetchPreparedPlan(&qkey)) == NULL)
			{
				StringInfoData querybuf;
				char		fkrelname[MAX_QUOTED_REL_NAME_LEN];
				char		attname[MAX_QUOTED_NAME_LEN];
				char		paramname[16];
				const char *querysep;
				Oid			queryoids[RI_MAX_NUMKEYS];

				/* ----------
				 * The query string built is
				 *	SELECT 1 FROM ONLY <fktable> WHERE $1 = fkatt1 [AND ...]
				 * The type id's for the $ parameters are those of the
				 * corresponding PK attributes.
				 * ----------
				 */
				initStringInfo(&querybuf);
				quoteRelationName(fkrelname, fk_rel);
				appendStringInfo(&querybuf, "SELECT 1 FROM ONLY %s x",
								 fkrelname);
				querysep = "WHERE";
				for (i = 0; i < riinfo.nkeys; i++)
				{
					Oid			pk_type = RIAttType(pk_rel, riinfo.pk_attnums[i]);
					Oid			fk_type = RIAttType(fk_rel, riinfo.fk_attnums[i]);

					quoteOneName(attname,
								 RIAttName(fk_rel, riinfo.fk_attnums[i]));
					sprintf(paramname, "$%d", i + 1);
					ri_GenerateQual(&querybuf, querysep,
									paramname, pk_type,
									riinfo.pf_eq_oprs[i],
									attname, fk_type);
					querysep = "AND";
					queryoids[i] = pk_type;
				}
				appendStringInfo(&querybuf, " FOR SHARE OF x");

				/* Prepare and save the plan */
				qplan = ri_PlanCheck(querybuf.data, riinfo.nkeys, queryoids,
									 &qkey, fk_rel, pk_rel, true);
			}

			/*
			 * We have a plan now. Run it to check for existing references.
			 */
			ri_PerformCheck(&qkey, qplan,
							fk_rel, pk_rel,
							old_row, NULL,
							true,		/* must detect new rows */
							SPI_OK_SELECT,
							NameStr(riinfo.conname));

			if (SPI_finish() != SPI_OK_FINISH)
				elog(ERROR, "SPI_finish failed");

			heap_close(fk_rel, RowShareLock);

			return PointerGetDatum(NULL);

			/*
			 * Handle MATCH PARTIAL restrict delete.
			 */
		case FKCONSTR_MATCH_PARTIAL:
			ereport(ERROR,
					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
					 errmsg("MATCH PARTIAL not yet implemented")));
			return PointerGetDatum(NULL);
	}

	/*
	 * Never reached
	 */
	elog(ERROR, "invalid confmatchtype");
	return PointerGetDatum(NULL);
}


/* ----------
 * RI_FKey_noaction_upd -
 *
 *	Give an error and roll back the current transaction if the
 *	update has resulted in a violation of the given referential
 *	integrity constraint.
 * ----------
 */
Datum
RI_FKey_noaction_upd(PG_FUNCTION_ARGS)
{
	TriggerData *trigdata = (TriggerData *) fcinfo->context;
	RI_ConstraintInfo riinfo;
	Relation	fk_rel;
	Relation	pk_rel;
	HeapTuple	new_row;
	HeapTuple	old_row;
	RI_QueryKey qkey;
	SPIPlanPtr	qplan;
	int			i;

	/*
	 * Check that this is a valid trigger call on the right time and event.
	 */
	ri_CheckTrigger(fcinfo, "RI_FKey_noaction_upd", RI_TRIGTYPE_UPDATE);

	/*
	 * Get arguments.
	 */
	ri_FetchConstraintInfo(&riinfo,
						   trigdata->tg_trigger, trigdata->tg_relation, true);

	/*
	 * Nothing to do if no column names to compare given
	 */
	if (riinfo.nkeys == 0)
		return PointerGetDatum(NULL);

	/*
	 * Get the relation descriptors of the FK and PK tables and the new and
	 * old tuple.
	 *
	 * fk_rel is opened in RowShareLock mode since that's what our eventual
	 * SELECT FOR SHARE will get on it.
	 */
	fk_rel = heap_open(riinfo.fk_relid, RowShareLock);
	pk_rel = trigdata->tg_relation;
	new_row = trigdata->tg_newtuple;
	old_row = trigdata->tg_trigtuple;

	switch (riinfo.confmatchtype)
	{
			/* ----------
			 * SQL3 11.9 <referential constraint definition>
			 *	Gereral rules 6) a) iv):
			 *		MATCH <unspecified> or MATCH FULL
			 *			... ON DELETE CASCADE
			 * ----------
			 */
		case FKCONSTR_MATCH_UNSPECIFIED:
		case FKCONSTR_MATCH_FULL:
			ri_BuildQueryKeyFull(&qkey, &riinfo,
								 RI_PLAN_NOACTION_UPD_CHECKREF);

			switch (ri_NullCheck(pk_rel, old_row, &qkey, RI_KEYPAIR_PK_IDX))
			{
				case RI_KEYS_ALL_NULL:
				case RI_KEYS_SOME_NULL:

					/*
					 * No check - MATCH FULL means there cannot be any
					 * reference to old key if it contains NULL
					 */
					heap_close(fk_rel, RowShareLock);
					return PointerGetDatum(NULL);

				case RI_KEYS_NONE_NULL:

					/*
					 * Have a full qualified key - continue below
					 */
					break;
			}

			/*
			 * No need to check anything if old and new keys are equal
			 */
			if (ri_KeysEqual(pk_rel, old_row, new_row, &riinfo, true))
			{
				heap_close(fk_rel, RowShareLock);
				return PointerGetDatum(NULL);
			}

			if (ri_Check_Pk_Match(pk_rel, fk_rel, old_row, &riinfo))
			{
				/*
				 * There's either another row, or no row could match this one.
				 * In either case, we don't need to do the check.
				 */
				heap_close(fk_rel, RowShareLock);
				return PointerGetDatum(NULL);
			}

			if (SPI_connect() != SPI_OK_CONNECT)
				elog(ERROR, "SPI_connect failed");

			/*
			 * Fetch or prepare a saved plan for the noaction update lookup if
			 * foreign references exist
			 */
			if ((qplan = ri_FetchPreparedPlan(&qkey)) == NULL)
			{
				StringInfoData querybuf;
				char		fkrelname[MAX_QUOTED_REL_NAME_LEN];
				char		attname[MAX_QUOTED_NAME_LEN];
				char		paramname[16];
				const char *querysep;
				Oid			queryoids[RI_MAX_NUMKEYS];

				/* ----------
				 * The query string built is
				 *	SELECT 1 FROM ONLY <fktable> WHERE $1 = fkatt1 [AND ...]
				 * The type id's for the $ parameters are those of the
				 * corresponding PK attributes.
				 * ----------
				 */
				initStringInfo(&querybuf);
				quoteRelationName(fkrelname, fk_rel);
				appendStringInfo(&querybuf, "SELECT 1 FROM ONLY %s x",
								 fkrelname);
				querysep = "WHERE";
				for (i = 0; i < riinfo.nkeys; i++)
				{
					Oid			pk_type = RIAttType(pk_rel, riinfo.pk_attnums[i]);
					Oid			fk_type = RIAttType(fk_rel, riinfo.fk_attnums[i]);

					quoteOneName(attname,
								 RIAttName(fk_rel, riinfo.fk_attnums[i]));
					sprintf(paramname, "$%d", i + 1);
					ri_GenerateQual(&querybuf, querysep,
									paramname, pk_type,
									riinfo.pf_eq_oprs[i],
									attname, fk_type);
					querysep = "AND";
					queryoids[i] = pk_type;
				}
				appendStringInfo(&querybuf, " FOR SHARE OF x");

				/* Prepare and save the plan */
				qplan = ri_PlanCheck(querybuf.data, riinfo.nkeys, queryoids,
									 &qkey, fk_rel, pk_rel, true);
			}