ri_triggers.c

来自「PostgreSQL7.4.6 for Linux」· C语言 代码 · 共 2,399 行 · 第 1/5 页

}


/* ----------
 * 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,
				  Oid tgoid, int match_type,
				  int tgnargs, char **tgargs)
{
	void	   *qplan;
	RI_QueryKey qkey;
	int			i;
	bool		result;

	ri_BuildQueryKeyPkCheck(&qkey, tgoid,
							RI_PLAN_CHECK_LOOKUPPK, pk_rel,
							tgnargs, tgargs);

	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 (match_type)
			{
				case RI_MATCH_TYPE_FULL:
				case RI_MATCH_TYPE_UNSPECIFIED:

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

				case RI_MATCH_TYPE_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)
	{
		char		querystr[MAX_QUOTED_REL_NAME_LEN + 100 +
							(MAX_QUOTED_NAME_LEN + 32) * RI_MAX_NUMKEYS];
		char		pkrelname[MAX_QUOTED_REL_NAME_LEN];
		char		attname[MAX_QUOTED_NAME_LEN];
		const char *querysep;
		Oid			queryoids[RI_MAX_NUMKEYS];

		/* ----------
		 * The query string built is
		 *	SELECT 1 FROM ONLY <pktable> WHERE pkatt1 = $1 [AND ...]
		 * The type id's for the $ parameters are those of the
		 * corresponding FK attributes. Thus, ri_PlanCheck could
		 * eventually fail if the parser cannot identify some way
		 * how to compare these two types by '='.
		 * ----------
		 */
		quoteRelationName(pkrelname, pk_rel);
		snprintf(querystr, sizeof(querystr), "SELECT 1 FROM ONLY %s x", pkrelname);
		querysep = "WHERE";
		for (i = 0; i < qkey.nkeypairs; i++)
		{
			quoteOneName(attname,
			 tgargs[RI_FIRST_ATTNAME_ARGNO + i * 2 + RI_KEYPAIR_PK_IDX]);
			snprintf(querystr + strlen(querystr), sizeof(querystr) - strlen(querystr), " %s %s = $%d",
					 querysep, attname, i + 1);
			querysep = "AND";
			queryoids[i] = SPI_gettypeid(pk_rel->rd_att,
									 qkey.keypair[i][RI_KEYPAIR_PK_IDX]);
		}
		strcat(querystr, " FOR UPDATE OF x");

		/* Prepare and save the plan */
		qplan = ri_PlanCheck(querystr, qkey.nkeypairs, 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;
	int			tgnargs;
	char	  **tgargs;
	Relation	fk_rel;
	Relation	pk_rel;
	HeapTuple	old_row;
	RI_QueryKey qkey;
	void	   *qplan;
	int			i;
	int			match_type;

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

	tgnargs = trigdata->tg_trigger->tgnargs;
	tgargs = trigdata->tg_trigger->tgargs;

	/*
	 * Nothing to do if no column names to compare given
	 */
	if (tgnargs == 4)
		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 UPDATE will get on it.
	 */
	fk_rel = heap_open(trigdata->tg_trigger->tgconstrrelid, RowShareLock);
	pk_rel = trigdata->tg_relation;
	old_row = trigdata->tg_trigtuple;

	match_type = ri_DetermineMatchType(tgargs[RI_MATCH_TYPE_ARGNO]);
	if (ri_Check_Pk_Match(pk_rel, fk_rel,
						  old_row, trigdata->tg_trigger->tgoid,
						  match_type, tgnargs, tgargs))
	{
		/*
		 * 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 (match_type)
	{
			/* ----------
			 * SQL3 11.9 <referential constraint definition>
			 *	Gereral rules 6) a) iv):
			 *		MATCH <unspecified> or MATCH FULL
			 *			... ON DELETE CASCADE
			 * ----------
			 */
		case RI_MATCH_TYPE_UNSPECIFIED:
		case RI_MATCH_TYPE_FULL:
			ri_BuildQueryKeyFull(&qkey, trigdata->tg_trigger->tgoid,
								 RI_PLAN_NOACTION_DEL_CHECKREF,
								 fk_rel, pk_rel,
								 tgnargs, tgargs);

			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)
			{
				char		querystr[MAX_QUOTED_REL_NAME_LEN + 100 +
							(MAX_QUOTED_NAME_LEN + 32) * RI_MAX_NUMKEYS];
				char		fkrelname[MAX_QUOTED_REL_NAME_LEN];
				char		attname[MAX_QUOTED_NAME_LEN];
				const char *querysep;
				Oid			queryoids[RI_MAX_NUMKEYS];

				/* ----------
				 * The query string built is
				 *	SELECT 1 FROM ONLY <fktable> WHERE fkatt1 = $1 [AND ...]
				 * The type id's for the $ parameters are those of the
				 * corresponding PK attributes. Thus, ri_PlanCheck could
				 * eventually fail if the parser cannot identify some way
				 * how to compare these two types by '='.
				 * ----------
				 */
				quoteRelationName(fkrelname, fk_rel);
				snprintf(querystr, sizeof(querystr), "SELECT 1 FROM ONLY %s x", fkrelname);
				querysep = "WHERE";
				for (i = 0; i < qkey.nkeypairs; i++)
				{
					quoteOneName(attname,
								 tgargs[RI_FIRST_ATTNAME_ARGNO + i * 2 + RI_KEYPAIR_FK_IDX]);
					snprintf(querystr + strlen(querystr), sizeof(querystr) - strlen(querystr), " %s %s = $%d",
							 querysep, attname, i + 1);
					querysep = "AND";
					queryoids[i] = SPI_gettypeid(pk_rel->rd_att,
									 qkey.keypair[i][RI_KEYPAIR_PK_IDX]);
				}
				strcat(querystr, " FOR UPDATE OF x");

				/* Prepare and save the plan */
				qplan = ri_PlanCheck(querystr, qkey.nkeypairs, 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,
							tgargs[RI_CONSTRAINT_NAME_ARGNO]);

			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 RI_MATCH_TYPE_PARTIAL:
			ereport(ERROR,
					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
					 errmsg("MATCH PARTIAL not yet implemented")));
			return PointerGetDatum(NULL);
	}

	/*
	 * Never reached
	 */
	elog(ERROR, "invalid match_type");
	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;
	int			tgnargs;
	char	  **tgargs;
	Relation	fk_rel;
	Relation	pk_rel;
	HeapTuple	new_row;
	HeapTuple	old_row;
	RI_QueryKey qkey;
	void	   *qplan;
	int			i;
	int			match_type;

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

	tgnargs = trigdata->tg_trigger->tgnargs;
	tgargs = trigdata->tg_trigger->tgargs;

	/*
	 * Nothing to do if no column names to compare given
	 */
	if (tgnargs == 4)
		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 UPDATE will get on it.
	 */
	fk_rel = heap_open(trigdata->tg_trigger->tgconstrrelid, RowShareLock);
	pk_rel = trigdata->tg_relation;
	new_row = trigdata->tg_newtuple;
	old_row = trigdata->tg_trigtuple;

	match_type = ri_DetermineMatchType(tgargs[RI_MATCH_TYPE_ARGNO]);

	switch (match_type)
	{
			/* ----------
			 * SQL3 11.9 <referential constraint definition>
			 *	Gereral rules 6) a) iv):
			 *		MATCH <unspecified> or MATCH FULL
			 *			... ON DELETE CASCADE
			 * ----------
			 */
		case RI_MATCH_TYPE_UNSPECIFIED:
		case RI_MATCH_TYPE_FULL:
			ri_BuildQueryKeyFull(&qkey, trigdata->tg_trigger->tgoid,
								 RI_PLAN_NOACTION_UPD_CHECKREF,
								 fk_rel, pk_rel,
								 tgnargs, tgargs);

			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, &qkey,
							 RI_KEYPAIR_PK_IDX))
			{
				heap_close(fk_rel, RowShareLock);
				return PointerGetDatum(NULL);
			}

			if (ri_Check_Pk_Match(pk_rel, fk_rel,
								  old_row, trigdata->tg_trigger->tgoid,
								  match_type, tgnargs, tgargs))
			{
				/*
				 * 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)
			{
				char		querystr[MAX_QUOTED_REL_NAME_LEN + 100 +
							(MAX_QUOTED_NAME_LEN + 32) * RI_MAX_NUMKEYS];
				char		fkrelname[MAX_QUOTED_REL_NAME_LEN];
				char		attname[MAX_QUOTED_NAME_LEN];
				const char *querysep;
				Oid			queryoids[RI_MAX_NUMKEYS];

				/* ----------
				 * The query string built is
				 *	SELECT 1 FROM ONLY <fktable> WHERE fkatt1 = $1 [AND ...]
				 * The type id's for the $ parameters are those of the
				 * corresponding PK attributes. Thus, ri_PlanCheck could
				 * eventually fail if the parser cannot identify some way
				 * how to compare these two types by '='.
				 * ----------
				 */
				quoteRelationName(fkrelname, fk_rel);
				snprintf(querystr, sizeof(querystr), "SELECT 1 FROM ONLY %s x", fkrelname);
				querysep = "WHERE";
				for (i = 0; i < qkey.nkeypairs; i++)
				{
					quoteOneName(attname,
								 tgargs[RI_FIRST_ATTNAME_ARGNO + i * 2 + RI_KEYPAIR_FK_IDX]);
					snprintf(querystr + strlen(querystr), sizeof(querystr) - strlen(querystr), " %s %s = $%d",
							 querysep, attname, i + 1);
					querysep = "AND";
					queryoids[i] = SPI_gettypeid(pk_rel->rd_att,
									 qkey.keypair[i][RI_KEYPAIR_PK_IDX]);
				}
				strcat(querystr, " FOR UPDATE OF x");

				/* Prepare and save the plan */
				qplan = ri_PlanCheck(querystr, qkey.nkeypairs, 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,
							tgargs[RI_CONSTRAINT_NAME_ARGNO]);