DB2存储过程如何编写和执行

db2执行文件参数:
-t 表示语句使用默认的语句终结符——分号;  
-v 表示使用冗长模式,这样 DB2 会显示每一条正在执行命令的信息;  
-f 表示其后就是脚本文件;  
-z表示其后的信息记录文件用于记录屏幕的输出,方便以后的分析(这是可选的,但我们建议使用该选项)。
当使用了-t选项而没有标明语句终结符,则分号(;)会默认为语句的终结符。有时可能会出现使用另外的终结符的情况,例如用SQL PL 编写的的脚本使用其它的符号而不是默认的分号,因为分号在SQL PL 是用于定义数据库对象过程中的语句结束。
-d --end的简称,最后一个结束符
存储过程:
;作为DB2默认的SQL命令结束符,即你执行的不是一个创建存储过程的语句,而是多条不完整的SQL语句。
语句中最后一个;换成其它符号,如@,然后使用db2 -td@ -vf insert_log_test.sql(txt、sql都可以) 指定@为命令结束符。

一个简单的存储过程:
vi insert_log_test.sql

CREATE OR REPLACE PROCEDURE INSERT_LOG_TEST()
begin
atomic declare i int default 0;
  while(i <10000)
  do insert into log_test values (i,'中间提交的事务');
  set i=i+1;
  end while;
end
@

[db2inst1@t3-dtpoc-dtpoc-web04 liys]$ db2 -td@ -vf insert_log_test.sql
CREATE OR REPLACE PROCEDURE INSERT_LOG_TEST()
begin 
atomic declare i int default 0;
  while(i <10000) 
  do insert into log_test values (i,'中间提交的事务');
  set i=i+1;
  end while;
end

DB20000I  The SQL command completed successfully.

如果我们把最后一个@删的,然后改成;然后执行db2 -tvf会发生什么?DB2会不会把文件看出一个存储过程,而是普通的DDL语句来执行,以;为DDL等sql的分隔符

[db2inst1@t3-dtpoc-dtpoc-web04 liys]$ db2 -tvf insert_log_test.sql
CREATE OR REPLACE PROCEDURE INSERT_LOG_TEST()
begin 
atomic declare i int default 0
DB21034E  The command was processed as an SQL statement because it was not a 
valid Command Line Processor command.  During SQL processing it returned:
SQL0104N  An unexpected token "END-OF-STATEMENT" was found following "lare i 
int default 0".  Expected tokens may include:  "".  LINE 
NUMBER=3.  SQLSTATE=42601

while(i <10000) do insert into log_test values (i,'中间提交的事务')
DB21034E  The command was processed as an SQL statement because it was not a 
valid Command Line Processor command.  During SQL processing it returned:
SQL0104N  An unexpected token "while(i <10000) do" was found following 
"BEGIN-OF-STATEMENT".  Expected tokens may include:  "".  
SQLSTATE=42601

set i=i+1
DB21034E  The command was processed as an SQL statement because it was not a 
valid Command Line Processor command.  During SQL processing it returned:
SQL0206N  "I" is not valid in the context where it is used.  SQLSTATE=42703

end while
DB21034E  The command was processed as an SQL statement because it was not a 
valid Command Line Processor command.  During SQL processing it returned:
SQL0104N  An unexpected token "END-OF-STATEMENT" was found following "end 
while".  Expected tokens may include:  "JOIN ".  SQLSTATE=42601

end
DB21034E  The command was processed as an SQL statement because it was not a 
valid Command Line Processor command.  During SQL processing it returned:
SQL0104N  An unexpected token "END-OF-STATEMENT" was found following "end".  
Expected tokens may include:  "JOIN ".  SQLSTATE=42601

调用存储过程:
[db2inst1@t3-dtpoc-dtpoc-web04 liys]$ db2 "select count(*) from log_test"

1          
-----------
     260000

  1 record(s) selected.

[db2inst1@t3-dtpoc-dtpoc-web04 liys]$ db2 "call insert_log_test()"       

  Return Status = 0
[db2inst1@t3-dtpoc-dtpoc-web04 liys]$ db2 "select count(*) from log_test"

1          
-----------
     270000

  1 record(s) selected.

db2 "call insert_log_test()"执行的很快,不到1秒就插入成功了,而MYSQL相同的存储过程需要大概26秒左右,没想到会这么慢。。。

直接执行存储过程:返回结果也很快,不到1秒。
[db2inst1@t3-dtpoc-dtpoc-web04 ~]$ db2 "begin atomic declare i int default 0;while(i <10000) do insert into log_test values (i,'中间提交的事务');set i=i+1;end while;end"
DB20000I  The SQL command completed successfully.

来看看MYSQL为啥这么慢,首先看他的存储过程定义:

vi insert_log_test.sql

delimiter //                            #定义标识符为双斜杠
drop procedure if exists insert_log_test;          #如果存在test存储过程则删除
create procedure insert_log_test()                 #创建无参存储过程,名称为test
begin
    declare i int;                      #申明变量
    set i = 0;                          #变量赋值
    while i < 10000 do                     #结束循环的条件: 当i大于10时跳出while循环
        insert into log_test values (i,'中间提交的事务+++++++++**********++++++++:q');    #往test表添加数据
        set i = i + 1;                  #循环一次,i加一
    end while;                          #结束while循环

end
//                                      #结束定义语句

插入10000条需要21秒多
mysql> call insert_log_test();
Query OK, 1 row affected (21.43 sec)

什么原因呢?怀疑是每插入一条就commit一次,一共commit了10000次,而DB2是插入10000条后提交了一次而已,下面来验证下
vi insert_log_test.sql
delimiter //
drop procedure if exists insert_log_test;
create procedure insert_log_test()
begin
    declare i int;
    set i = 0;
     start transaction;
    while i < 10000 do
        insert into log_test values (i,'中间提交的事务+++++++++**********++++++++');
        set i = i + 1;
    end while;
    commit;

end//
delimiter ;


mysql> source /home/mysql/liys/insert_log_test.sql;
Query OK, 0 rows affected, 1 warning (0.00 sec)

Query OK, 0 rows affected (0.00 sec)

mysql> call insert_log_test();
Query OK, 0 rows affected (0.26 sec)

mysql> select count(*) from log_test;
+----------+
| count(*) |
+----------+
|   410000 |
+----------+
1 row in set (0.15 sec)

mysql> call insert_log_test();
Query OK, 0 rows affected (0.27 sec)

mysql> select count(*) from log_test;
+----------+
| count(*) |
+----------+
|   420000 |
+----------+
1 row in set (0.15 sec)

结果证明猜想是对的

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