pl/sql编程

二.pl/sql 编程方面

1.自治事务:8i以上版本，不影响主事务。
在存储过程的is＼as
后面声明PRAGMA AUTONOMOUS_TRANSACTION; 
自治事务防止嵌套提交，使事务在自己的事务区内提交或回滚不会影响其他的事务。

2、包
   包说明(package specification)，包头,存放关于包的内容的信息，定义包的用户可见的过程、
   函数，数据类型和变量
     create or replace package  tt_aa  as 
        v1  varchar2(10);
        v2  varchar2(10);
        v3  number;
        v4  boolean;
        procedure proc1(x  number);
        procedure proc2(y varchar2);
        procedure proc3(z  number);
        function my_add(x number,y number) return number;
      end;
   包主体（package body)是可选的
     create or replace package  body  tt_aa as 
       procedure proc1(x number) as 
         begin
           v1:=to_char(x);
         end;
       procedure proc2(y varchar2) as 
         begin
           v2:=y;
         end;
       procedure proc3(z number) as 
         begin
           v1:=z;
         end;
       procedure proc4(x number,y number) return number as 
         begin
           return x+y;
         end;
     end;
     
   调用
     begin  
         tt_aa.proc1(6);
         dbms_output.put_line(to_char(tt_aa.my_add(1,3));
     end;

3、动态sql(使用dbms_sql)

    create or replace procedure my_execute(sql_string in varchar2) as 
      v_cursor  number;
      v_numrows  interger;
    begin
       v_cursor:=dbms_sql.open_cursor;
       dbms_sql.parse(v_cursor,sql_string,dbms_sql.v7);
       v_numrows:=dbms_sql.execute(v_cursor);
       dbms_sql.close_cursor(v_cursor);
    end;
     
    则可以
     sql>exec  my_execute(’select * from tab’);
     sql>exec  my_execute(’insert into test value’||’(’||’’’ddd’’’||’)’);
     sql>exec  my_execute(’commit’);
     
  对于查询方面的可以如下方式：
  比如想用游标查询一个表，但是这个表是分月的，每个月可能表名都会改变。
  create or replace procedure proc_test as
    v_curid  integer;
    v_result integer;
    v_strSql varchar2(255);
    v_userid okcai.userid%type;
    v_username okcai.username%type;
  begin
     v_strSql := ’select * from okcai_’||to_char(sysdate,’yyyymm’);
     v_curid := dbms_sql.open_cursor;
     dbms_sql.parse(v_curid,v_strSql,dbms_sql.v7);
     dbms_sql.define_column(v_curid,1,v_userid);
     dbms_sql.define_column(v_curid,2,v_username,10);  --必须指定大小
     v_result := dbms_sql.execute(v_curid);
     loop
        if dbms_sql.fetch_rows(v_curid) = 0 then
            exit; --没有了 ，退出循环
        end if;
        dbms_sql.column_value(v_curid,1,v_userid);
        dbms_sql.column_value(v_curid,2,v_username);
        dbms_output.put_line(v_userid);
        dbms_output.put_line(v_username);
     end loop;
     dbms_sql.close(v_curid);
  end;

4、用EXECUTE IMMEDIATE
    <1>. 在PL/SQL运行DDL语句
    begin
      execute immediate ’set role all’;
    end;
    <2>. 给动态语句传值(USING 子句)
    declare
       l_depnam varchar2(20) := ’testing’;
       l_loc    varchar2(10) := ’Dubai’;
    begin
      execute immediate ’insert into dept values  (:1, :2, :3)’
              using 50, l_depnam, l_loc;
      commit;
    end;
   <3>. 从动态语句检索值(INTO子句)
   declare
      l_cnt    varchar2(20);
   begin
      execute immediate ’select count(1) from emp’
          into l_cnt;
      dbms_output.put_line(l_cnt);
  end;
   <4>. 动态调用例程.例程中用到的绑定变量参数必须指定参数类型.?认为IN类型,其它类型必须显式指定
 declare
    l_routin   varchar2(100) := ’gen2161.get_rowcnt’;
  l_tblnam   varchar2(20) := ’emp’;
    l_cnt      number;
    l_status   varchar2(200);
 begin
    execute immediate ’begin ’ || l_routin || ’(:2, :3, :4); end;’
       using in l_tblnam, out l_cnt, in out l_status;

    if l_status != ’OK’ then
        dbms_output.put_line(’error’);
    end if;
 end;
   <5>. 将返回值传递到PL/SQL记录类型;同样也可用%rowtype变量
  declare
    type empdtlrec is record (empno  number(4),
                           ename  varchar2(20),
                           deptno  number(2));
    empdtl empdtlrec;
  begin
    execute immediate ’select empno, ename, deptno ’ ||
                   ’from emp where empno = 7Array34’
      into empdtl;
  end;
   <6>. 传递并检索值.INTO子句用在USING子句前
  declare
    l_dept    pls_integer := 20;
    l_nam     varchar2(20);
    l_loc     varchar2(20);
  begin
  execute immediate ’select dname, loc from dept where deptno = :1’
       into l_nam, l_loc
       using l_dept ;
  end;
   <7>. 多行查询选项.对此选项用insert语句填充临时表，用临时表进行进一步的处理,也可以用REF cursors纠正此缺憾.
  declare
    l_sal   pls_integer := 2000;
  begin
    execute immediate ’insert into temp(empno, ename) ’ ||
                   ’          select empno, ename from emp ’ ||
                   ’          where  sal > :1’
      using l_sal;
    commit;
  end;
   <8>. 完成update的returning功能
       update可以用returning返回修改以后的值。比如:
  UPDATE employees
   SET job_id =’SA_MAN’, salary = salary + 1000, department_id = 140
   WHERE last_name = ’Jones’
    RETURNING salary*0.25, last_name, department_id
     INTO :bnd1, :bnd2, :bnd3;
       用execute immediate来完成的时候，可以用
  declare
    l_sal   pls_integer;
  begin
    execute immediate ’update employees SET salary = salary + 1000 where last_name=’’okcai’’ RETURNING INTO :1’
   returning into v_sql;
    commit;
  end;
      
5、用ref cursor来完成动态游标的功能
declare
 type ct is ref cursor;
 cc ct;
 v_notify acc_woff_notify%rowtype;
begin
 open cc for ’select * from acc_woff_notify’;
 loop
  fetch cc into v_notify;
  exit when cc%notfound;
  dbms_output.put_line(v_notify.done_code);
 end loop;
 close cc;
end;      
6、重新编译
    对失效的过程
    sql>exec  dbms_utility.compile_schema(schema);
    如：
    sql>exec  dbms_utility.compile_schema(scott);
7.存储过程使用table类型
<1>.字符串数组
declare
 type regionType is table of varchar2(3) index by binary_integer;
 v_listRegion regionType;
 i number(2):=0;
begin
 v_listRegion(1):=’571’;
 v_listRegion(2):=’572’;
 v_listRegion(3):=’573’;
 v_listRegion(4):=’574’;
 v_listRegion(5):=’575’;
 v_listRegion(6):=’576’;
 v_listRegion(7):=null;
 i := 1;
 while i<= v_listRegion.last loop
  dbms_output.put_line( v_listRegion(i) );
  i := v_listRegion.next(i);
 end loop;
end;

<2>.rowtype数组
declare
 type CmUserType is table of cm_user%rowtype index by binary_integer;
 v_listUser CmUserType;
 i number(5):=0;
 r_user cm_user%rowtype;
begin
 
 i := 1;
 for r_user in (select * from cm_user where rownum<=5) loop
  v_listUser(i):= r_user;
  i := i + 1;
 end loop;
 
 i := 1;
 while i<= v_listUser.last loop
  dbms_output.put_line( v_listUser(i).bill_id );
  i := v_listUser.next(i);
 end loop;
end;

<3>. record数组
declare
 type recCmUserType is record  (bill_id cm_user.bill_id%type,cust_name varchar2(25));
 type CmUserType is table of recCmUserType index by binary_integer;
 v_listUser CmUserType;
 i number(5):=0;
 r_user cm_user%rowtype;
begin
 
 i := 1;
 for r_user in (select * from cm_user where rownum<=5) loop
  v_listUser(i).bill_id:= r_user.bill_id;
  v_listUser(i).cust_name:= ’客户’||i;
  i := i + 1;
 end loop;
 
 i := 1;
 while i<= v_listUser.last loop
  dbms_output.put_line( v_listUser(i).bill_id );
  dbms_output.put_line( v_listUser(i).cust_name );
  i := v_listUser.next(i);
 end loop;
end;
8、存储函数和过程
     查看函数和过程的状态
     SQL>select object_name,status from user_objects where object_type=’FUNCTION’;
     SQL>select object_name,status from user_objects where object_type=’PROCEDURE’;
     
     查看函数和过程的源代码
        SQL>set long 1000
        SQL>set pagesize 0
 SQL>set trimspool on
     SQL>select text from all_source where owner=user and name=upper(’&plsql_name’);
     
Array、触发器
    
     查看触发器

     set long 50000;
     set heading off;
     set pagesize 2000;

     select
     ’create or replace trigger "’ ||
              trigger_name || ’"’ || chr(10)||
      decode( substr( trigger_type, 1, 1 ),
              ’A’, ’AFTER’, ’B’, ’BEFORE’, ’I’, ’INSTEAD OF’ ) ||
                   chr(10) ||
      triggering_event || chr(10) ||
      ’ON "’ || table_owner || ’"."’ ||
            table_name || ’"’ || chr(10) ||
      decode( instr( trigger_type, ’EACH ROW’ ), 0, null,
                 ’FOR EACH ROW’ ) || chr(10) ,
      trigger_body
     from user_triggers;
10. 加密ORACLE的存储过程
用wrap命令,如:
    下列存储过程内容放在AA.SQL文件中
    create or replace procedure testCCB(i in number) as
    begin
    dbms_output.put_line(’输入参数是’||to_char(i));
    end;

    SQL>wrap iname=a.sql;
    PL/SQL Wrapper: Release 8.1.7.0.0 - Production on Tue Nov 27 22:26:48 2001
    Copyright (c) Oracle Corporation 1ArrayArray3, 2000.  All Rights Reserved.
    Processing a.sql to a.plb
    提示a.sql转换为a.plb，这就是加密了的脚本，执行a.plb即可生成加密了的存储过程
    运行a.plb
    SQL> @a.plb ;
11.怎么样利用游标更新数据
cursor c1 is 
select * from tablename 
    where name is null for update [of column]
...
update tablename set column = ...
where current of c1;

但是如果这种方式打开以后做了commit，则下次fetch会报ora-01002错误
12.怎样自定义异常
pragma_exception_init(exception_name,error_number);
如果立即抛出异常
raise_application_error(error_number,error_msg,true|false);
其中number从-20000到-20ArrayArrayArray，错误信息最大2048B
异常变量
SQLCODE 错误代码
SQLERRM 错误信息

13.在pl/sql中执行DDL语句
<1>、8i以下版本dbms_sql包
<2>、8i以上版本还可以用
execute immediate sql;
dbms_utility.exec_ddl_statement(’sql’);
14.用java写存储过程包
<1>
create or replace and compile 
java source 
named "CHelloWorld" as
public class HelloWorld
{
  public static String print()
  {
         return System.out.println("Hello,World");
  }
};
/


<2>
create or replace function my_helloWorld return varchar2
as language java
name ’HelloWorld.print() return java.lang.String’;
/

<3>
select my_helloWorld from dual;