ruleutils.c

来自「PostgreSQL7.4.6 for Linux」· C语言 代码 · 共 2,475 行 · 第 1/5 页

								SnapshotNow, 1, skey);

	ht_trig = systable_getnext(tgscan);

	if (!HeapTupleIsValid(ht_trig))
		elog(ERROR, "could not find tuple for trigger %u", trigid);

	trigrec = (Form_pg_trigger) GETSTRUCT(ht_trig);

	/*
	 * Start the trigger definition. Note that the trigger's name should
	 * never be schema-qualified, but the trigger rel's name may be.
	 */
	initStringInfo(&buf);

	tgname = NameStr(trigrec->tgname);
	appendStringInfo(&buf, "CREATE %sTRIGGER %s ",
					 trigrec->tgisconstraint ? "CONSTRAINT " : "",
					 quote_identifier(tgname));

	if (TRIGGER_FOR_BEFORE(trigrec->tgtype))
		appendStringInfo(&buf, "BEFORE");
	else
		appendStringInfo(&buf, "AFTER");
	if (TRIGGER_FOR_INSERT(trigrec->tgtype))
	{
		appendStringInfo(&buf, " INSERT");
		findx++;
	}
	if (TRIGGER_FOR_DELETE(trigrec->tgtype))
	{
		if (findx > 0)
			appendStringInfo(&buf, " OR DELETE");
		else
			appendStringInfo(&buf, " DELETE");
		findx++;
	}
	if (TRIGGER_FOR_UPDATE(trigrec->tgtype))
	{
		if (findx > 0)
			appendStringInfo(&buf, " OR UPDATE");
		else
			appendStringInfo(&buf, " UPDATE");
	}
	appendStringInfo(&buf, " ON %s ",
					 generate_relation_name(trigrec->tgrelid));

	if (trigrec->tgisconstraint)
	{
		if (trigrec->tgconstrrelid != InvalidOid)
			appendStringInfo(&buf, "FROM %s ",
						 generate_relation_name(trigrec->tgconstrrelid));
		if (!trigrec->tgdeferrable)
			appendStringInfo(&buf, "NOT ");
		appendStringInfo(&buf, "DEFERRABLE INITIALLY ");
		if (trigrec->tginitdeferred)
			appendStringInfo(&buf, "DEFERRED ");
		else
			appendStringInfo(&buf, "IMMEDIATE ");

	}

	if (TRIGGER_FOR_ROW(trigrec->tgtype))
		appendStringInfo(&buf, "FOR EACH ROW ");
	else
		appendStringInfo(&buf, "FOR EACH STATEMENT ");

	appendStringInfo(&buf, "EXECUTE PROCEDURE %s(",
					 generate_function_name(trigrec->tgfoid, 0, NULL));

	if (trigrec->tgnargs > 0)
	{
		bytea	   *val;
		bool		isnull;
		char	   *p;
		int			i;

		val = (bytea *) fastgetattr(ht_trig,
									Anum_pg_trigger_tgargs,
									tgrel->rd_att, &isnull);
		if (isnull)
			elog(ERROR, "tgargs is null for trigger %u", trigid);
		p = (char *) VARDATA(val);
		for (i = 0; i < trigrec->tgnargs; i++)
		{
			if (i > 0)
				appendStringInfo(&buf, ", ");
			appendStringInfoChar(&buf, '\'');
			while (*p)
			{
				/* escape quotes and backslashes */
				if (*p == '\'' || *p == '\\')
					appendStringInfoChar(&buf, '\\');
				appendStringInfoChar(&buf, *p++);
			}
			p++;
			appendStringInfoChar(&buf, '\'');
		}
	}

	/* We deliberately do not put semi-colon at end */
	appendStringInfo(&buf, ")");

	/*
	 * Create the result as a TEXT datum, and free working data
	 */
	len = buf.len + VARHDRSZ;
	trigdef = (text *) palloc(len);
	VARATT_SIZEP(trigdef) = len;
	memcpy(VARDATA(trigdef), buf.data, buf.len);

	pfree(buf.data);

	systable_endscan(tgscan);

	heap_close(tgrel, AccessShareLock);

	PG_RETURN_TEXT_P(trigdef);
}

/* ----------
 * get_indexdef			- Get the definition of an index
 *
 * In the extended version, there is a colno argument as well as pretty bool.
 *	if colno == 0, we want a complete index definition.
 *	if colno > 0, we only want the Nth index key's variable or expression.
 * ----------
 */
Datum
pg_get_indexdef(PG_FUNCTION_ARGS)
{
	Oid			indexrelid = PG_GETARG_OID(0);

	return pg_get_indexdef_worker(indexrelid, 0, 0);
}

Datum
pg_get_indexdef_ext(PG_FUNCTION_ARGS)
{
	Oid			indexrelid = PG_GETARG_OID(0);
	int32		colno = PG_GETARG_INT32(1);
	bool		pretty = PG_GETARG_BOOL(2);
	int			prettyFlags;

	prettyFlags = pretty ? PRETTYFLAG_PAREN | PRETTYFLAG_INDENT : 0;
	return pg_get_indexdef_worker(indexrelid, colno, prettyFlags);
}

static Datum
pg_get_indexdef_worker(Oid indexrelid, int colno, int prettyFlags)
{
	text	   *indexdef;
	HeapTuple	ht_idx;
	HeapTuple	ht_idxrel;
	HeapTuple	ht_am;
	Form_pg_index idxrec;
	Form_pg_class idxrelrec;
	Form_pg_am	amrec;
	List	   *indexprs;
	List	   *context;
	Oid			indrelid;
	int			len;
	int			keyno;
	Oid			keycoltype;
	StringInfoData buf;
	char	   *str;
	char	   *sep;

	/*
	 * Fetch the pg_index tuple by the Oid of the index
	 */
	ht_idx = SearchSysCache(INDEXRELID,
							ObjectIdGetDatum(indexrelid),
							0, 0, 0);
	if (!HeapTupleIsValid(ht_idx))
		elog(ERROR, "cache lookup failed for index %u", indexrelid);
	idxrec = (Form_pg_index) GETSTRUCT(ht_idx);

	indrelid = idxrec->indrelid;
	Assert(indexrelid == idxrec->indexrelid);

	/*
	 * Fetch the pg_class tuple of the index relation
	 */
	ht_idxrel = SearchSysCache(RELOID,
							   ObjectIdGetDatum(indexrelid),
							   0, 0, 0);
	if (!HeapTupleIsValid(ht_idxrel))
		elog(ERROR, "cache lookup failed for relation %u", indexrelid);
	idxrelrec = (Form_pg_class) GETSTRUCT(ht_idxrel);

	/*
	 * Fetch the pg_am tuple of the index' access method
	 */
	ht_am = SearchSysCache(AMOID,
						   ObjectIdGetDatum(idxrelrec->relam),
						   0, 0, 0);
	if (!HeapTupleIsValid(ht_am))
		elog(ERROR, "cache lookup failed for access method %u",
			 idxrelrec->relam);
	amrec = (Form_pg_am) GETSTRUCT(ht_am);

	/*
	 * Get the index expressions, if any.  (NOTE: we do not use the
	 * relcache versions of the expressions and predicate, because we want
	 * to display non-const-folded expressions.)
	 */
	if (!heap_attisnull(ht_idx, Anum_pg_index_indexprs))
	{
		Datum		exprsDatum;
		bool		isnull;
		char	   *exprsString;

		exprsDatum = SysCacheGetAttr(INDEXRELID, ht_idx,
									 Anum_pg_index_indexprs, &isnull);
		Assert(!isnull);
		exprsString = DatumGetCString(DirectFunctionCall1(textout,
														  exprsDatum));
		indexprs = (List *) stringToNode(exprsString);
		pfree(exprsString);
	}
	else
		indexprs = NIL;

	context = deparse_context_for(get_rel_name(indrelid), indrelid);

	/*
	 * Start the index definition.	Note that the index's name should
	 * never be schema-qualified, but the indexed rel's name may be.
	 */
	initStringInfo(&buf);

	if (!colno)
		appendStringInfo(&buf, "CREATE %sINDEX %s ON %s USING %s (",
						 idxrec->indisunique ? "UNIQUE " : "",
						 quote_identifier(NameStr(idxrelrec->relname)),
						 generate_relation_name(indrelid),
						 quote_identifier(NameStr(amrec->amname)));

	/*
	 * Report the indexed attributes
	 */
	sep = "";
	for (keyno = 0; keyno < idxrec->indnatts; keyno++)
	{
		AttrNumber	attnum = idxrec->indkey[keyno];

		if (!colno)
			appendStringInfo(&buf, sep);
		sep = ", ";

		if (attnum != 0)
		{
			/* Simple index column */
			char	   *attname;

			attname = get_relid_attribute_name(indrelid, attnum);
			if (!colno || colno == keyno + 1)
				appendStringInfo(&buf, "%s", quote_identifier(attname));
			keycoltype = get_atttype(indrelid, attnum);
		}
		else
		{
			/* expressional index */
			Node	   *indexkey;

			if (indexprs == NIL)
				elog(ERROR, "too few entries in indexprs list");
			indexkey = (Node *) lfirst(indexprs);
			indexprs = lnext(indexprs);
			/* Deparse */
			str = deparse_expression_pretty(indexkey, context, false, false,
											prettyFlags, 0);
			if (!colno || colno == keyno + 1)
			{
				/* Need parens if it's not a bare function call */
				if (indexkey && IsA(indexkey, FuncExpr) &&
					((FuncExpr *) indexkey)->funcformat == COERCE_EXPLICIT_CALL)
					appendStringInfo(&buf, "%s", str);
				else
					appendStringInfo(&buf, "(%s)", str);
			}
			keycoltype = exprType(indexkey);
		}

		/*
		 * Add the operator class name
		 */
		if (!colno)
			get_opclass_name(idxrec->indclass[keyno], keycoltype,
							 &buf);
	}

	if (!colno)
	{
		appendStringInfoChar(&buf, ')');

		/*
		 * If it's a partial index, decompile and append the predicate
		 */
		if (!heap_attisnull(ht_idx, Anum_pg_index_indpred))
		{
			Node	   *node;
			Datum		predDatum;
			bool		isnull;
			char	   *predString;

			/* Convert text string to node tree */
			predDatum = SysCacheGetAttr(INDEXRELID, ht_idx,
										Anum_pg_index_indpred, &isnull);
			Assert(!isnull);
			predString = DatumGetCString(DirectFunctionCall1(textout,
															 predDatum));
			node = (Node *) stringToNode(predString);
			pfree(predString);

			/*
			 * If top level is a List, assume it is an implicit-AND
			 * structure, and convert to explicit AND.	This is needed for
			 * partial index predicates.
			 */
			if (node && IsA(node, List))
				node = (Node *) make_ands_explicit((List *) node);
			/* Deparse */
			str = deparse_expression_pretty(node, context, false, false,
											prettyFlags, 0);
			appendStringInfo(&buf, " WHERE %s", str);
		}
	}

	/*
	 * Create the result as a TEXT datum, and free working data
	 */
	len = buf.len + VARHDRSZ;
	indexdef = (text *) palloc(len);
	VARATT_SIZEP(indexdef) = len;
	memcpy(VARDATA(indexdef), buf.data, buf.len);

	pfree(buf.data);

	ReleaseSysCache(ht_idx);
	ReleaseSysCache(ht_idxrel);
	ReleaseSysCache(ht_am);

	PG_RETURN_TEXT_P(indexdef);
}


/*
 * pg_get_constraintdef
 *
 * Returns the definition for the constraint, ie, everything that needs to
 * appear after "ALTER TABLE ... ADD CONSTRAINT <constraintname>".
 */
Datum
pg_get_constraintdef(PG_FUNCTION_ARGS)
{
	Oid			constraintId = PG_GETARG_OID(0);

	return pg_get_constraintdef_worker(constraintId, 0);
}

Datum
pg_get_constraintdef_ext(PG_FUNCTION_ARGS)
{
	Oid			constraintId = PG_GETARG_OID(0);
	bool		pretty = PG_GETARG_BOOL(1);
	int			prettyFlags;

	prettyFlags = pretty ? PRETTYFLAG_PAREN | PRETTYFLAG_INDENT : 0;
	return pg_get_constraintdef_worker(constraintId, prettyFlags);
}


static Datum
pg_get_constraintdef_worker(Oid constraintId, int prettyFlags)
{
	text	   *result;
	StringInfoData buf;
	int			len;
	Relation	conDesc;
	SysScanDesc conscan;
	ScanKeyData skey[1];
	HeapTuple	tup;
	Form_pg_constraint conForm;

	/*
	 * Fetch the pg_constraint row.  There's no syscache for pg_constraint
	 * so we must do it the hard way.
	 */
	conDesc = heap_openr(ConstraintRelationName, AccessShareLock);

	ScanKeyEntryInitialize(&skey[0], 0x0,
						   ObjectIdAttributeNumber, F_OIDEQ,
						   ObjectIdGetDatum(constraintId));

	conscan = systable_beginscan(conDesc, ConstraintOidIndex, true,
								 SnapshotNow, 1, skey);

	tup = systable_getnext(conscan);
	if (!HeapTupleIsValid(tup))
		elog(ERROR, "could not find tuple for constraint %u", constraintId);
	conForm = (Form_pg_constraint) GETSTRUCT(tup);

	initStringInfo(&buf);

	switch (conForm->contype)
	{
		case CONSTRAINT_FOREIGN:
			{
				Datum		val;
				bool		isnull;
				const char *string;

				/* Start off the constraint definition */
				appendStringInfo(&buf, "FOREIGN KEY (");

				/* Fetch and build referencing-column list */
				val = heap_getattr(tup, Anum_pg_constraint_conkey,
								   RelationGetDescr(conDesc), &isnull);
				if (isnull)
					elog(ERROR, "null conkey for constraint %u",
						 constraintId);

				decompile_column_index_array(val, conForm->conrelid, &buf);

				/* add foreign relation name */
				appendStringInfo(&buf, ") REFERENCES %s(",
							 generate_relation_name(conForm->confrelid));

				/* Fetch and build referenced-column list */
				val = heap_getattr(tup, Anum_pg_constraint_confkey,
								   RelationGetDescr(conDesc), &isnull);
				if (isnull)
					elog(ERROR, "null confkey for constraint %u",
						 constraintId);

				decompile_column_index_array(val, conForm->confrelid, &buf);

				appendStringInfo(&buf, ")");

				/* Add match type */
				switch (conForm->confmatchtype)
				{
					case FKCONSTR_MATCH_FULL:
						string = " MATCH FULL";
						break;
					case FKCONSTR_MATCH_PARTIAL:
						string = " MATCH PARTIAL";
						break;
					case FKCONSTR_MATCH_UNSPECIFIED:
						string = "";
						break;
					default:
						elog(ERROR, "unrecognized confmatchtype: %d",
							 conForm->confmatchtype);
						string = "";	/* keep compiler quiet */
						break;
				}
				appendStringInfo(&buf, "%s", string);

				/* Add ON UPDATE and ON DELETE clauses, if needed */
				switch (conForm->confupdtype)
				{
					case FKCONSTR_ACTION_NOACTION:
						string = NULL;	/* suppress default */
						break;
					case FKCONSTR_ACTION_RESTRICT:
						string = "RESTRICT";
						break;
					case FKCONSTR_ACTION_CASCADE:
						string = "CASCADE";
						break;
					case FKCONSTR_ACTION_SETNULL:
						string = "SET NULL";
						break;
					case FKCONSTR_ACTION_SETDEFAULT:
						string = "SET DEFAULT";
						break;
					default:
						elog(ERROR, "unrecognized confupdtype: %d",
							 conForm->confupdtype);
						string = NULL;	/* keep compiler quiet */
						break;
				}
				if (string)
					appendStringInfo(&buf, " ON UPDATE %s", string);

				switch (conForm->confdeltype)
				{
					case FKCONSTR_ACTION_NOACTION:
						string = NULL;	/* suppress default */
						break;
					case FKCONSTR_ACTION_RESTRICT:
						string = "RESTRICT";