PL/SQL-4 動態SQL
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第四部分:動態SQL
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/*
1.什麼是動態SQL?
動態SQL是指在執行PL/SQL塊時動態輸入SQL語句。在PL/SQL塊中只能執行DDL(create、alter、drop)、DCL
(grant、revoke)或比較靈活的SQL語句(如select子句不帶where條件);
動態SQL的效能不如靜態SQL,但是比較靈活;
在PL/SQL塊中編寫動態SQL語句時需要將SQL語句存放到字串變數中而且SQL語句可以包含佔位符(以冒號開始);
2.動態SQL的語法
2.1 使用execute immediate語句
可以處理多數動態SQL操作如:DDL語句(create、alter、drop)、DML語句(insert、update、delete)、DCL(grant、revoke)
以及單行的select子句;但是不能處理多行查詢語句。
2.2 使用open...for,fetch和close語句
在遊標中使用。
2.3 使用批量動態SQL語句
*/
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1. 使用execute immediate
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1.1 使用execute immediate處理DDL語句
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--案例01:使用execute immediate處理DDL語句--create
declare
create_table varchar2(200);
begin
create_table:='create table ' ||'&table_name' ||'(sid int, sno int)';
execute immediate create_table ;
end;
--案例02:使用execute immediate處理DDL語句---alter
declare
alter_table varchar2(200);
begin
alter_table:='alter table &target_table_name modify &column_name varchar2(10)';
execute immediate alter_table ;
end;
--案例03:使用execute immediate處理DDL語句---drop
declare
drop_table varchar2(200);
begin
drop_table:='drop table ' ||'&target_table_name';
execute immediate drop_table ;
end;
--案例04:使用execute immediate處理DDL語句--drop table
create or replace procedure drop_table (table_name varchar2)
is
sql_sta varchar2(200);
begin
sql_sta:='drop table ' ||table_name;
execute immediate sql_sta;
end;
--呼叫方法:
exec drop_table('accp');
--案例05:使用execute immediate處理DDL語句--create+select
declare
select_sta varchar2(200);
emp_rec emp%rowtype;
begin
execute immediate
'create table sodi(sid int, sno int)';
select_sta:='select * from emp where empno=:id';
execute immediate select_sta into emp_rec using &1; /*使用佔位符時,這個佔位符是在引號內使用的*/
end;
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1.2 使用execute immediate處理DCL語句
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--案例01:使用execute immediate處理DCL語句--grant
create or replace procedure grant_priv(priv varchar2, username varchar2)
is
priv_stat varchar2(200);
begin
priv_stat:=' grant '|| priv || ' to ' || username; --注意字串和連線符之間的空格
execute immediate priv_stat;
end;
--呼叫方法
exec grant_priv('create session', 'scott');
--案例02:使用execute immediate處理DCL語句--revoke
create or replace procedure revoke_priv(priv varchar2, username varchar2)
is
priv_stat varchar2(200);
begin
priv_stat:=' revoke '|| priv || ' from ' || username; --注意字串和連線符之間的空格
execute immediate priv_stat;
end;
--呼叫方法
exec revoke_priv('create session', 'scott');
----------------------------------------------------------------
1.3.使用execute immediate處理DML語句
----------------------------------------------------------------
1.處理無佔位符和return子句的DML語句
--案例01:查詢子句:select
declare
sql_stat varchar2(100);
begin
sql_stat:='select * from emp';
execute immediate sql_stat;
end;
--案例02:處理無佔位符和return子句的DML語句--insert
declare
insert_table varchar2(200);
begin
insert_table:='insert into &table_name values (&sid, &sno)';
execute immediate insert_table;
end;
--案例03:處理無佔位符和return子句的DML語句--update
declare
update_table varchar2(200);
begin
update_table:='update &table_name set &column_name=&new_value ';
execute immediate update_table;
end;
--案例06:處理無佔位符和return子句的DML語句--delete
declare
delete_table varchar2(200);
begin
delete_table:='delete from &table_name ';
execute immediate delete_table;
end;
--案例05:新建一個表然後插入資料--create+insert
declare
create_table varchar2(200);
begin
create_table:='create table &table_name(sid int, sno int)';
execute immediate create_table ;
end;
declare
insert_table varchar2(200);
begin
insert_table:='insert into &table_name values (&sid, &sno)';
execute immediate insert_table;
end;
--案例06:同時實現新建一個表並插入資料--create+insert
declare
create_table varchar2(200);
insert_table varchar2(200);
begin
create_table:='create table &table_name (sid int, sno int)';
execute immediate create_table ;
insert_table:='insert into &table_name values (&sid, &sno)';
execute immediate insert_table;
end;
--案例07:同時實現新建一個表並插入資料--create+insert+update
/*
這裡也可以分開寫
*/
declare
create_table varchar2(200);
insert_table varchar2(200);
update_table varchar2(200);
begin
create_table:='create table &table_name (sid int, sno int)';
execute immediate create_table ;
insert_table:='insert into &table_name values (&sid, &sno)';
execute immediate insert_table;
update_table:='update &table_name set &column_name=&new_value where sid=&old_value';
execute immediate update_table;
end;
--案例08:同時實現新建一個表並插入資料--create+insert+update+delete
declare
create_table varchar2(200);
insert_table varchar2(200);
update_table varchar2(200);
delete_table varchar2(200);
begin
create_table:='create table &table_name (sid int, sno int)';
execute immediate create_table ;
insert_table:='insert into &table_name values (&sid, &sno)';
execute immediate insert_table;
update_table:='update &table_name set &column_name=&new_value where sid=&old_value';
execute immediate update_table;
delete_table:='delete from &delete_tablename';
execute immediate delete_table;
end;
--案例08:同時實現新建一個表並插入資料--create+insert+update+delete+insert
declare
create_table varchar2(200);
insert_table varchar2(200);
update_table varchar2(200);
delete_table varchar2(200);
re_insert_table varchar2(200);
begin
create_table:='create table &table_name (sid int, sno int)';
execute immediate create_table ;
insert_table:='insert into &table_name values (&sid, &sno)';
execute immediate insert_table;
update_table:='update &table_name set &column_name=&new_value where sid=&old_value';
execute immediate update_table;
delete_table:='delete from &delete_tablename';
execute immediate delete_table;
re_insert_table:='insert into &re_table_name values (&new_sid, &new_sno)';
execute immediate re_insert_table;
end;
2.處理佔位符的DML語句
--案例01:處理佔位符的DML語句:create+insert
declare
create_table varchar2(200);
insert_table varchar2(200);
begin
create_table:='create table &table_name (sid int, sno int)';
execute immediate create_table ;
insert_table:='insert into &target_table_name values (:sid, :sno)';
execute immediate insert_table using &2,&3;
end;
--案例02:處理佔位符的DML語句:create+insert_update
declare
create_table varchar2(200);
insert_table varchar2(200);
update_table varchar2(200);
begin
create_table:='create table &table_name (sid int, sno int)';
execute immediate create_table ;
insert_table:='insert into &target_table_name values (:sid, :sno)';
execute immediate insert_table using &1,&2;
update_table:='update &update_tablename set &update_column_name=:new_value where &condition_column=:old_value ';
execute immediate update_table using &3 ,&4;
end;
---or
declare
create_table varchar2(200);
insert_table varchar2(200);
update_table varchar2(200);
begin
create_table:='create table &新建的表名 (sid int, sno int)';
execute immediate create_table ;
insert_table:='insert into &插入資料的表名 values (:sid, :sno)';
execute immediate insert_table using &sid的值 ,&sno的值;
update_table:='update &被更新的表名 set &更新的列名=:new_value where &條件列=:old_value ';
execute immediate update_table using &新值 ,&條件列的值;
end;
--案例03:處理佔位符的DML語句:create+update+insert+delete
declare
create_table varchar2(200);
insert_table varchar2(200);
update_table varchar2(200);
delete_table varchar2(200);
begin
create_table:='create table &table_name (sid int, sno int)';
execute immediate create_table ;
insert_table:='insert into &target_table_name values (:sid, :sno)';
execute immediate insert_table using &1,&2;
update_table:='update &update_tablename set &update_column_name=:new_value where &update_condition_column=:delete_condition_column_value ';
execute immediate update_table using &3 ,&4;
delete_table:='delete from &dele_table_name where &delete_condition_column=:delete_condition_column_value';
execute immediate delete_table using &5;
end;
---執行過程:
SQL> declare
2 create_table varchar2(200);
3 insert_table varchar2(200);
4 update_table varchar2(200);
5 delete_table varchar2(200);
6 begin
7 create_table:='create table &table_name (sid int, sno int)';
8 execute immediate create_table ;
9
10 insert_table:='insert into &target_table_name values (:sid, :sno)';
11 execute immediate insert_table using &1,&2;
12
13 update_table:='update &update_tablename set &update_column_name=:new_value
where &update_condition_column=:delete_condition_column_value ';
14 execute immediate update_table using &3 ,&4;
15
16 delete_table:='delete from &dele_table_name where &delete_condition_column=
:delete_condition_column_value';
17 execute immediate delete_table using &5;
18 end;
19 /
輸入 table_name 的值: sz
原值 7: create_table:='create table &table_name (sid int, sno int)';
新值 7: create_table:='create table sz (sid int, sno int)';
輸入 target_table_name 的值: sz
原值 10: insert_table:='insert into &target_table_name values (:sid, :sno)';
新值 10: insert_table:='insert into sz values (:sid, :sno)';
輸入 1 的值: 101
輸入 2 的值: 201
原值 11: execute immediate insert_table using &1,&2;
新值 11: execute immediate insert_table using 101,201;
輸入 update_tablename 的值: sz
輸入 update_column_name 的值: sid
輸入 update_condition_column 的值: sno
原值 13: update_table:='update &update_tablename set &update_column_name=:new_
value where &update_condition_column=:delete_condition_column_value ';
新值 13: update_table:='update sz set sid=:new_value where sno=:delete_conditi
on_column_value ';
輸入 3 的值: 1001
輸入 4 的值: 201
原值 14: execute immediate update_table using &3 ,&4;
新值 14: execute immediate update_table using 1001 ,201;
輸入 dele_table_name 的值: sz
輸入 delete_condition_column 的值: sno
原值 16: delete_table:='delete from &dele_table_name where &delete_condition_c
olumn=:delete_condition_column_value';
新值 16: delete_table:='delete from sz where sno=:delete_condition_column_valu
e';
輸入 5 的值: 201
原值 17: execute immediate delete_table using &5;
新值 17: execute immediate delete_table using 201;
PL/SQL 過程已成功完成。
SQL> select * from sz;
未選定行
3.處理包含returning子句的DML語句
--案例01:處理包含returning子句的DML語句--create+insert+update
declare
create_table varchar2(200);
insert_table varchar2(200);
update_table varchar2(200);
res varchar2(100);
begin
create_table:='create table &new_table_name (sid int, sno int)';
execute immediate create_table;
insert_table:='insert into &insert_target_table_name values (:sid, :sno)';
execute immediate insert_table using &1,&2 ;
update_table:='update &update_target_table_name set &udpate_column_name=:new_value where &condition_column_name=:old_value returning &returning_name into :res';
execute immediate update_table using &3,&4
returning into res;
dbms_output.put_line('the result is : ' ||res);
end;