函数支持自治事务

自治事务可以在函数中定义，标识符为PRAGMA AUTONOMOUS_TRANSACTION，其余语法与函数语法相同，示例如下。

gaussdb=# create table t4(a int, b int, c text);

gaussdb=# CREATE OR REPLACE function autonomous_32(a int ,b int ,c text) RETURN int AS 
DECLARE 
	PRAGMA AUTONOMOUS_TRANSACTION;
BEGIN
	insert into t4 values(a, b, c);
	return 1;
END;
/
CREATE FUNCTION
gaussdb=# CREATE OR REPLACE function autonomous_33(num1 int) RETURN int AS 
DECLARE 
	num3 int := 220;
	tmp int;
	PRAGMA AUTONOMOUS_TRANSACTION;
BEGIN
	num3 := num3/num1;
	return num3;
EXCEPTION
	WHEN division_by_zero THEN
		select autonomous_32(num3, num1, sqlerrm) into tmp;
		return 0;
END;
/
CREATE FUNCTION

gaussdb=# select autonomous_33(0);
 autonomous_33
---------------
             0
(1 row)

gaussdb=# select * from t4;
  a  | b |        c
-----+---+------------------
 220 | 0 | division by zero
(1 row)