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【我和openGauss的故事】带有out参数的存储过程及自定义函数的重载测试
老老老JR老北
发布于 2023-9-12 11:12
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背景
先说下数据库里说的函数重载是什么。比如我们知道数据库可能会有同名的函数，但是函数的参数声明不一样
select to_char(sysdate,'yyyymmdd') from dual;
select to_char(0.1,'fm9990.00') from dual;上面这种情况就叫函数的重载，虽然函数名一致，但实际在数据库中对应的是不同的函数。
在ORACLE中，本身并不支持同名对象，ORACLE中的函数重载，基本都是在PACKAGE中实现的，比如上面的to_char函数，其实是在一个名为"STANDARD"的PACKAGE中。
然后在ORACLE中，对于是否重载的判断，会同时考虑出入参的个数和类型，因此支持这样的重载
procedure proc1(p1 number,p2 varchar2,p3 out number);
procedure proc1(p1 number,p2 varchar2);而在openGauss中，支持在非package中重载存储过程，默认情况是只考虑存储过程名称以及入参的匹配，即上述两个同名存储过程由于都是有两个入参，且类型一致，会被识别为同一个存储过程，即不能重载。
不过，在openGauss中，有参数来控制是否支持重载
相关参数
官方文档：https://docs.opengauss.org/zh/docs/5.0.0/docs/DatabaseReference/%E5%B9%B3%E5%8F%B0%E5%92%8C%E5%AE%A2%E6%88%B7%E7%AB%AF%E5%85%BC%E5%AE%B9%E6%80%A7.html
set behavior_compat_options='proc_outparam_override';官方文档中，对此参数的说明为
控制存储过程出参的重载行为，打开该参数后，对于存储过程只有out出参部分不同的情况下，也可以正常调用。
结合我上面提到的那个重载的例子，这段话就好理解了。
但是，实际上proc_outparam_override这个选项不仅如此
测试
一、创建
A、package外的procedure
1.关闭选项，创建in参数一致但out参数不一致的同名procedure，报错
testdb=# set behavior_compat_options='';
SET
testdb=# show behavior_compat_options;
behavior_compat_options
-------------------------
(1 row)
testdb=# create procedure test_outparam_1(p1 int,p2 out int) is
testdb$# begin
testdb$# raise notice 'this is test_outparam_1(p1 int,p2 out int)';
testdb$# end;
testdb$# /
CREATE PROCEDURE
testdb=# create procedure test_outparam_1(p1 int,p2 out int,p3 out int) is
testdb$# begin
testdb$# raise notice 'this is test_outparam_1(p1 int,p2 out int,p3 out int)';
testdb$# end;
testdb$# /
ERROR: function "test_outparam_1" already exists with same argument types
testdb=#2.用create or replace procedure，会直接覆盖同名procedure
testdb=# create or replace procedure test_outparam_1(p1 int,p2 out int,p3 out int) is
testdb$# begin
testdb$# raise notice 'this is test_outparam_1(p1 int,p2 out int,p3 out int)';
testdb$# end;
testdb$# /
CREATE PROCEDURE
testdb=# declare
testdb-# x int;
testdb-# begin
testdb$# test_outparam_1(1,x);
testdb$# end;
testdb$# /
ERROR: function "test_outparam_1" with 2 parameters doesn't exist
CONTEXT: SQL statement "CALL test_outparam_1(1,x)"
PL/pgSQL function inline_code_block line 4 at SQL statement
testdb=# declare
testdb-# x int;
testdb-# y int;
testdb-# begin
testdb$# test_outparam_1(1,x,y);
testdb$# end;
testdb$# /
NOTICE: this is test_outparam_1(p1 int,p2 out int,p3 out int)
ANONYMOUS BLOCK EXECUTE
testdb=#3.创建同名，但in参数类型不一致的procedure,发现也会将之前同名的procedure覆盖掉
testdb=# create or replace procedure test_outparam_1(p1 text,p2 out int,p3 out int) is
testdb$# begin
testdb$# raise notice 'this is test_outparam_1(p1 text,p2 out int,p3 out int)';
testdb$# end;
testdb$# /
CREATE PROCEDURE
testdb=# declare
testdb-# x int;
testdb-# y int;
testdb-# begin
testdb$# test_outparam_1(1,x,y);
testdb$# end;
testdb$# /
NOTICE: this is test_outparam_1(p1 text,p2 out int,p3 out int)
ANONYMOUS BLOCK EXECUTE
testdb=# \df test_outparam_1
List of functions
Schema | Name | Result data type | Argument data types | Type | fencedmode | propackage | prokind
--------+-----------------+------------------+-----------------------------------------+--------+------------+------------+---------
public | test_outparam_1 | record | p1 text, OUT p2 integer, OUT p3 integer | normal | f | f | p
(1 row)
testdb=#4.打开选项后，上述测试结果不会发生变化
B、package外的function(ORACLE语法风格)
1.关闭选项，创建in参数一致但out参数不一致的同名function，报错
testdb=# set behavior_compat_options='';
SET
testdb=# create function test_outparam_2(p1 int,p2 out int) return int is
testdb$# begin
testdb$# raise notice 'this is test_outparam_2(p1 int,p2 out int)';
testdb$# return 1;
testdb$# end;
testdb$# /
CREATE FUNCTION
testdb=# create function test_outparam_2(p1 int,p2 out int,p3 out int) return int is
testdb$# begin
testdb$# raise notice 'this is test_outparam_2(p1 int,p2 out int,p3 out int)';
testdb$# return 1;
testdb$# end;
testdb$# /
ERROR: function "test_outparam_2" already exists with same argument types
testdb=#2.用create or replace function ,会直接覆盖同名function
testdb=# create or replace function test_outparam_2(p1 int,p2 out int,p3 out int) return int is
testdb$# begin
testdb$# raise notice 'this is test_outparam_2(p1 int,p2 out int,p3 out int)';
testdb$# return 1;
testdb$# end;
testdb$# /
CREATE FUNCTION
testdb=# \df test_outparam_2
List of functions
Schema | Name | Result data type | Argument data types | Type | fencedmode | propackage | prokind
--------+-----------------+------------------+--------------------------------------------+--------+------------+------------+---------
public | test_outparam_2 | integer | p1 integer, OUT p2 integer, OUT p3 integer | normal | f | f | f
(1 row)
testdb=#3.创建同名，但in参数类型不一致的function,发现也会将之前同名的function覆盖掉
testdb=# create or replace function test_outparam_2(p1 text,p2 out int,p3 out int) return int is
testdb$# begin
testdb$# raise notice 'this is test_outparam_2(p1 text,p2 out int,p3 out int)';
testdb$# return 1;
testdb$# end;
testdb$# /
CREATE FUNCTION
testdb=# \df test_outparam_2
List of functions
Schema | Name | Result data type | Argument data types | Type | fencedmode | propackage | prokind
--------+-----------------+------------------+-----------------------------------------+--------+------------+------------+---------
public | test_outparam_2 | integer | p1 text, OUT p2 integer, OUT p3 integer | normal | f | f | f
(1 row)
testdb=#4.打开选项后，上述测试结果不会发生变化
C、package外的function(PG语法风格)
1.关闭选项，创建in参数一致但out参数不一致的同名function,报错
testdb=# create function test_outparam_3(p1 int,p2 out int) returns int as $$
testdb$# begin
testdb$# raise notice 'this is test_outparam_3(p1 int,p2 out int)';
testdb$# return 1;
testdb$# end;$$language plpgsql;
CREATE FUNCTION
testdb=# create function test_outparam_3(p1 int,p2 out int,p3 out int) returns int as $$
testdb$# begin
testdb$# raise notice 'this is test_outparam_3(p1 int,p2 out int,p3 out int)';
testdb$# return 1;
testdb$# end;$$language plpgsql;
ERROR: function "test_outparam_3" already exists with same argument types
testdb=#2.用create or replace function ,会直接覆盖同名function
testdb=# create or replace function test_outparam_3(p1 int,p2 out int,p3 out int) returns int as $$
testdb$# begin
testdb$# raise notice 'this is test_outparam_3(p1 int,p2 out int,p3 out int)';
testdb$# return 1;
testdb$# end;$$language plpgsql;
CREATE FUNCTION
testdb=# \df test_outparam_3
List of functions
Schema | Name | Result data type | Argument data types | Type | fencedmode | propackage | prokind
--------+-----------------+------------------+--------------------------------------------+--------+------------+------------+---------
public | test_outparam_3 | integer | p1 integer, OUT p2 integer, OUT p3 integer | normal | f | f | f
(1 row)
testdb=#3.创建同名，但in参数类型不一致的function,此时不会覆盖原有同名函数
testdb=# create or replace function test_outparam_3(p1 text,p2 out int,p3 out int) returns int as $$
testdb$# begin
testdb$# raise notice 'this is test_outparam_3(p1 text,p2 out int,p3 out int)';
testdb$# return 1;
testdb$# end;$$language plpgsql;
CREATE FUNCTION
testdb=# \df test_outparam_3
List of functions
Schema | Name | Result data type | Argument data types | Type | fencedmode | propackage | prokind
--------+-----------------+------------------+--------------------------------------------+--------+------------+------------+---------
public | test_outparam_3 | integer | p1 integer, OUT p2 integer, OUT p3 integer | normal | f | f | f
public | test_outparam_3 | integer | p1 text, OUT p2 integer, OUT p3 integer | normal | f | f | f
(2 rows)
testdb=#4.打开选项后，上述测试结果不会发生变化
D、PACKAGE内的procedure
1.关闭选项，入参一致，出参不一致的同名procedure,创建报错
testdb=# set behavior_compat_options='';
SET
testdb=# create package test_outparam_4 is
testdb$# procedure a(p1 int,p2 out int);
testdb$# procedure a(p1 int,p2 out int,p3 out int);
testdb$# end test_outparam_4;
testdb$# /
ERROR: can not override out param:a
LINE 2: procedure a(p1 int,p2 out int);2.打开选项，再次创建，不报错
testdb=# set behavior_compat_options='proc_outparam_override';
SET
testdb=# create package test_outparam_4 is
testdb$# procedure a(p1 int,p2 out int);
testdb$# procedure a(p1 int,p2 out int,p3 out int);
testdb$# end test_outparam_4;
testdb$# /
CREATE PACKAGE
testdb=#3.关闭选项，入参类型不一致，出参一致，创建成功(打开参数时，情况一样)
testdb=# set behavior_compat_options='';
SET
testdb=# create or replace package test_outparam_4 is
testdb$# procedure a(p1 int,p2 out int);
testdb$# procedure a(p1 text,p2 out int);
testdb$# end test_outparam_4;
testdb$# /
CREATE PACKAGE
testdb=#
testdb=# create type int_table is table of int;
CREATE TYPE
testdb=# create or replace package test_outparam_4 is
testdb$# procedure a(p1 int,p2 out int);
testdb$# procedure a(p1 int_table,p2 out int);
testdb$# end test_outparam_4;
testdb$# /
CREATE PACKAGE
testdb=#4.特殊情况1,procedure的名称和入参的自定义复合类型中的一个属性名一致时，会报错（此处与重载无关）
openGauss=# create type test_ttyy as (a int,b int);
CREATE TYPE
openGauss=# create or replace package test_outparam_4 is
openGauss$# procedure a(p1 test_ttyy,p2 out int);
openGauss$# end test_outparam_4;
openGauss$# /
ERROR: "a" is already an attribute of type test_ttyy
openGauss=#5.特殊情况2，带inout的参数，在关闭重载选项时，只会判断in的参数个数，不会判断参数的数据类型，一个inout参数相当于一个in参数和一个out参数，下例两个procedure都只有一个in参数，因此创建报错；但打开重载选项后，可以创建成功，此时inout视为一个参数，判断重复的规则变成了 “存储过程名称+总参数个数+按相同顺序的参数inout类型+按相同顺序参数数据类型”
testdb=# create package test_out is
testdb$# procedure p1(a date,b out text);
testdb$# procedure p1(a inout int);
testdb$# end test_out;
testdb$# /
ERROR: can not override out param:p1
LINE 2: procedure p1(a date,b out text);
testdb=# set behavior_compat_options='proc_outparam_override';
SET
testdb=# create or replace package test_out is
testdb$# procedure p1(a date,b out text);
testdb$# procedure p1(a inout int);
testdb$# end test_out;
testdb$# /
CREATE PACKAGE
testdb=# create or replace package test_out is
testdb$# procedure p1(a int,b out int);
testdb$# procedure p1(a inout int);
testdb$# end test_out;
testdb$# /
CREATE PACKAGE
testdb=# create or replace package test_out is
testdb$# procedure p1(a int,b out int);
testdb$# procedure p1(a inout int,b out int);
testdb$# end test_out;
testdb$# /
CREATE PACKAGEE、PACKAGE内的function
1.关闭选项，入参一致，出参不一致的同名function,创建报错
testdb=# set behavior_compat_options='';
SET
testdb=# create or replace package test_outparam_5 is
testdb$# function f1(p1 int,p2 out int) return int;
testdb$# function f1(p1 int,p2 out text) return int;
testdb$# end test_outparam_5;
testdb$# /
ERROR: function declared duplicate: f12.打开选项，再次创建，报错发生变化
testdb=# set behavior_compat_options='proc_outparam_override';
SET
testdb=# create or replace package test_outparam_5 is
testdb$# function f1(p1 int,p2 out int) return int;
testdb$# function f1(p1 int,p2 out text) return int;
testdb$# end test_outparam_5;
testdb$# /
ERROR: "f1" functions with plpgsql language and out params are not supported Overloaded.
DETAIL: N/A.
testdb=#3.关闭选项，入参类型不一致，出参一致，创建成功(打开选项时，情况一样)
testdb=# set behavior_compat_options='';
SET
testdb=# create or replace package test_outparam_5 is
testdb$# function f1(p1 int,p2 out int) return int;
testdb$# function f1(p1 text,p2 out int) return int;
testdb$# end test_outparam_5;
testdb$# /
CREATE PACKAGE
testdb=#二、使用
PLSQL block中使用
1.开启重载选项，调用package中的procedure,重载的procedure均可正常获取出参
testdb=# set behavior_compat_options='proc_outparam_override';
SET
testdb=# create or replace package test_outparam_6 is
testdb$# procedure a(p1 int,p2 out int);
testdb$# procedure a(p1 int,p2 out int,p3 out int);
testdb$# end test_outparam_6;
testdb$# /
CREATE PACKAGE
testdb=# create or replace package body test_outparam_6 is
testdb$# procedure a(p1 int,p2 out int) is
testdb$# begin
testdb$# p2:=p1;
testdb$# end;
testdb$# procedure a(p1 int,p2 out int,p3 out int) is
testdb$# begin
testdb$# p2:=p1*10;
testdb$# p3:=p1*10;
testdb$# end;
testdb$# end test_outparam_6;
testdb$# /
CREATE PACKAGE BODY
testdb=# declare
testdb-# x1 int:=1;
testdb-# x2 int;
testdb-# y1 int:=2;
testdb-# y2 int;
testdb-# y3 int;
testdb-# begin
testdb$# test_outparam_6.a(x1,x2);
testdb$# test_outparam_6.a(y1,y2,y3);
testdb$# raise notice '%,%',x1,x2;
testdb$# raise notice '%,%,%',y1,y2,y3;
testdb$# end;
testdb$# /
NOTICE: 1,1
NOTICE: 2,20,20
ANONYMOUS BLOCK EXECUTE
testdb=#2.关闭选项，调用包内带出参的procedure (无重载的情况)，可正常获取出参
testdb=# set behavior_compat_options='';
SET
testdb=# create or replace package test_outparam_6 is
testdb$# procedure a(p1 int,p2 out int);
testdb$# end test_outparam_6;
testdb$# /
CREATE PACKAGE
testdb=# create or replace package body test_outparam_6 is
testdb$# procedure a(p1 int,p2 out int) is
testdb$# begin
testdb$# p2:=p1;
testdb$# end;
testdb$# end test_outparam_6;
testdb$# /
CREATE PACKAGE BODY
testdb=# declare
testdb-# x1 int:=1;
testdb-# x2 int;
testdb-# begin
testdb$# test_outparam_6.a(x1,x2);
testdb$# raise notice '%,%',x1,x2;
testdb$# end;
testdb$# /
NOTICE: 1,1
ANONYMOUS BLOCK EXECUTE
testdb=#3.开启选项，调用包内带出参的函数，出参可正常获取
testdb=# set behavior_compat_options='proc_outparam_override';
SET
testdb=# create or replace package test_outparam_8 is
testdb$# function a(p1 int,p2 out int) return int;
testdb$# end test_outparam_8;
testdb$# /
CREATE PACKAGE
testdb=# create or replace package body test_outparam_8 is
testdb$# function a(p1 int,p2 out int) return int is
testdb$# begin
testdb$# p2:=p1;
testdb$# return p1+p2;
testdb$# end;
testdb$# end test_outparam_8;
testdb$# /
CREATE PACKAGE BODY
testdb=# declare
testdb-# x1 int:=1;
testdb-# x2 int;
testdb-# r int;
testdb-# begin
testdb$# r:=test_outparam_8.a(x1,x2);
testdb$# raise notice '%,%,%',x1,x2,r;
testdb$# end;
testdb$# /
NOTICE: 1,1,2
ANONYMOUS BLOCK EXECUTE
testdb=#4.关闭选项，调用包内带出参的函数,无法获得out参数的值
testdb=# set behavior_compat_options='';
SET
testdb=# create or replace package test_outparam_8 is
testdb$# function a(p1 int,p2 out int) return int;
testdb$# end test_outparam_8;
testdb$# /
CREATE PACKAGE
testdb=# create or replace package body test_outparam_8 is
testdb$# function a(p1 int,p2 out int) return int is
testdb$# begin
testdb$# p2:=p1;
testdb$# return p1+p2;
testdb$# end;
testdb$# end test_outparam_8;
testdb$# /
CREATE PACKAGE BODY
testdb=# declare
testdb-# x1 int:=1;
testdb-# x2 int;
testdb-# r int;
testdb-# begin
testdb$# r:=test_outparam_8.a(x1,x2);
testdb$# raise notice '%,%,%',x1,x2,r;
testdb$# end;
testdb$# /
NOTICE: 1,<NULL>,2
ANONYMOUS BLOCK EXECUTE
testdb=#SQL中使用
1.关闭重载选项，使用select 方式调用package中的procedure，传参只能传in参数，不能传out参数（带默认值的in参数可以不传）
testdb=# set behavior_compat_options='';
SET
testdb=# create or replace package test_outparam_6 is
testdb$# procedure a(p1 int,p2 out int);
testdb$# end test_outparam_6;
testdb$# /
CREATE PACKAGE
testdb=# create or replace package body test_outparam_6 is
testdb$# procedure a(p1 int,p2 out int) is
testdb$# begin
testdb$# p2:=p1;
testdb$# end;
testdb$# end test_outparam_6;
testdb$# /
CREATE PACKAGE BODY
testdb=# select test_outparam_6.a(1);
a
---
1
(1 row)
testdb=# select test_outparam_6.a(1,1);
ERROR: function test_outparam_6.a(integer, integer) does not exist
LINE 1: select test_outparam_6.a(1,1);
^
HINT: No function matches the given name and argument types. You might need to add explicit type casts.
CONTEXT: referenced column: a
testdb=#2.打开重载选项，使用select 方式调用package中的procedure，必须传满in和out参数,out参数只需要传对类型，值无实际意义（带默认值的in参数可以不传）
testdb=# set behavior_compat_options='proc_outparam_override';
SET
testdb=# create or replace package test_outparam_6 is
testdb$# procedure a(p1 int,p2 out int);
testdb$# end test_outparam_6;
testdb$# /
CREATE PACKAGE
testdb=# create or replace package body test_outparam_6 is
testdb$# procedure a(p1 int,p2 out int) is
testdb$# begin
testdb$# p2:=p1;
testdb$# end;
testdb$# end test_outparam_6;
testdb$# /
CREATE PACKAGE BODY
testdb=# select test_outparam_6.a(1);
ERROR: function test_outparam_6.a(integer) does not exist
LINE 1: select test_outparam_6.a(1);
^
HINT: No function matches the given name and argument types. You might need to add explicit type casts.
CONTEXT: referenced column: a
testdb=# select test_outparam_6.a(1,1);
a
---
1
(1 row)3.获取多个out参数的方法
testdb=# set behavior_compat_options='';
SET
testdb=# create or replace package test_outparam_6 is
testdb$# procedure a(p1 int,p2 out int,p3 out int);
testdb$# end test_outparam_6;
testdb$# /
CREATE PACKAGE
testdb=# create or replace package body test_outparam_6 is
testdb$# procedure a(p1 int,p2 out int,p3 out int) is
testdb$# begin
testdb$# p2:=p1;
testdb$# p3:=p1*10;
testdb$# end;
testdb$# end test_outparam_6;
testdb$# /
CREATE PACKAGE BODY
testdb=# select * from test_outparam_6.a(1);
p2 | p3
----+----
1 | 10
(1 row)
testdb=# set behavior_compat_options='proc_outparam_override';--打开重载
SET
testdb=# select * from test_outparam_6.a(1);
ERROR: function test_outparam_6.a(integer) does not exist
LINE 1: select * from test_outparam_6.a(1);
^
HINT: No function matches the given name and argument types. You might need to add explicit type casts.
testdb=# select * from test_outparam_6.a(1,2,3);
p2 | p3
----+----
1 | 10
(1 row)
testdb=#4.关闭重载选项，使用select 方式调用带出参的package内function
testdb=# set behavior_compat_options='';
SET
testdb=# create or replace package test_outparam_8 is
testdb$# function a(p1 int,p2 out int) return int;
testdb$# end test_outparam_8;
testdb$# /
CREATE PACKAGE
testdb=# create or replace package body test_outparam_8 is
testdb$# function a(p1 int,p2 out int) return int is
testdb$# begin
testdb$# p2:=p1;
testdb$# return p1+p2;
testdb$# end;
testdb$# end test_outparam_8;
testdb$# /
CREATE PACKAGE BODY
testdb=# select test_outparam_8.a(1);
a
---
2
(1 row)
testdb=# select test_outparam_8.a(1,1);
ERROR: function test_outparam_8.a(integer, integer) does not exist
LINE 1: select test_outparam_8.a(1,1);
^
HINT: No function matches the given name and argument types. You might need to add explicit type casts.
CONTEXT: referenced column: a
testdb=#5.打开重载选项，使用select 方式调用带出参的package内function
testdb=# set behavior_compat_options='proc_outparam_override';
SET
testdb=# create or replace package test_outparam_8 is
testdb$# function a(p1 int,p2 out int) return int;
testdb$# end test_outparam_8;
testdb$# /
CREATE PACKAGE
testdb=# create or replace package body test_outparam_8 is
testdb$# function a(p1 int,p2 out int) return int is
testdb$# begin
testdb$# p2:=p1;
testdb$# return p1+p2;
testdb$# end;
testdb$# end test_outparam_8;
testdb$# /
CREATE PACKAGE BODY
testdb=# select test_outparam_8.a(1);
ERROR: function test_outparam_8.a(integer) does not exist
LINE 1: select test_outparam_8.a(1);
^
HINT: No function matches the given name and argument types. You might need to add explicit type casts.
CONTEXT: referenced column: a
testdb=# select test_outparam_8.a(1,1);
a
---
2
(1 row)
testdb=#总结
对于openGauss
一、以下两条不会由于重载选项的差异发生行为改变
1.使用ORACLE风格语法的procedure和function，创建规则和ORACLE一致，同名对象直接覆盖
2.使用PG风格的FUNCTION，支持入参不一致的重载创建；对于入参一致，仅出参有差异的，会直接覆盖（如果return类型变化，创建会报错）
二、重载选项会控制package中的procedure能否创建仅出参不一致的重载，关闭选项时，重载规则为仅入参不匹配；开启选项时，重载规则为任意参数不匹配。
三、当有inout参数时，关闭重载选项，视为一个in参数和一个out参数，并且不再判断参数类型差异，重载必须要求入参个数不一致；开启重载选项时按上一条规则，即任意参数不匹配即可重载。
四、打开重载选项时，PLSQL中调用PROCEDURE和FUNCTION方法和ORACLE一致，均可正常获取出参的值；关闭重载选项时，调用FUNCTION无法获得出参的值。
五、打开重载选项时，使用SQL查询procedure和function，需要传满参数，包括所有的in和out参数；关闭重载选项时，只需要传in和inout参数。
文章转载自公众号：openGauss
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已于2023-9-12 11:12:18修改
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