PL_SQL:帶有分支和循環,面向過程
匿名塊:
declare(可選,聲明各種變量和遊標的地方)
begin(必要的,從此開始執行)
exception(抓取到異常後執行的)
end;
set serveroutput on;(默認是關閉)
--最簡單的PL/SQL語句塊
begin
dbms_output.put_line('HelloWorld!');
end;
--最簡單的語句塊
declare
v_name varchar2(20);
begin
v_name := 'myname';
dbms_output.put_line(v_name);
end;
--語句塊的組成
declare
v_name number := 0;
begin
v_name := 2/v_num;
dbms_output.put_line(v_name);
exception
when others then
dbms_output.put_line('error');
end;
--變量聲明
1. 變量名不能夠使用保留字,如from,select等
2. 第一個字符必須是字母
3. 變量名最多包含30個字符
4. 不要與數據庫表或者列同名
5. 每一行只能聲明一個變量
--常用變量類型
1. binary_integer: 整數,主要用來計數而不是用來表示字段類型,效率高
2. number: 數字類型
3. char: 定長字符串
4. varchar2: 變長字符串
5. date: 日期
6. long: 長字符串,最長2GB
7. boolean: 布爾類型,可以取值爲ture、false和null值,一定要給初值,無法打印
--變量聲明
declare
v_temp number(1);
v_count binary_integer := 0;
v_sal number(7,2) := 4000.00;
v_date date := sysdate;
v_pi constant number(3,2) := 3.14;
v_valid boolean := false;
v_name varchar2(20) not null := 'MyName';
begin
dbms_output.put_line('v_temp value:' || v_count);
end;
--變量聲明,使用%type屬性
/*註釋多行*/ --註釋一行
declare
v_empno number(4);
v_empno2 emp.empno%type;--用表內字段類型聲明變量類型
v_empno3 v_empno2%type;--用變量type屬性聲明變量類型
begin
dbms_output.put_line('Test');
end;
--簡單變量賦值
declare
v_name varchar2(20);
v_sal number(7,2);
v_sal2 number(7,2);
v_valid boolean := false;
v_date date;
begin
v_name := 'MyName';
v_sal := 23.77;
v_sal2 := 23.77;
v_valid := (v_sal = v_sal2);--判斷是否相等用=
v_date := to_date('1999-08-12 12:23:30','YYYY-MM-DD HH24:MI:SS');
end;
--Table變量類型,表示一個數組
declare
type type_table_emp_empno is table of emp.empno%type index by binary_integer;--首先聲明一個類型
v_empnos type_table_emp_empno;--再用這個類型聲明變量
begin
v_empnos(0) := 7369;
v_empnos(2) := 7839;
v_empnos(-1) := 9999;
dbms_output.put_line(v_empnos(-1));---1訪問不到,0,2可以訪問到
end;
--Record類型,表示一個類
declare
type type_record_dept is record
(
deptno dept.deptno%type,
dname dept.dname%tpye,
loc dept.loc%type
);
v_temp type_record_dept;
begin
v_temp.deptno := 50;
v_temp.dname := 'aaaa';
v_temp.loc := 'bj';
dbms_output.put_line(v_temp.deptno || ' ' || v_temp.dname);
end;
--使用%rowtype聲明record變量
declare
v_temp dept%rowtype;
begin
v_temp.deptno := 50;
v_temp.dname := 'aaaa';
v_temp.loc := 'bj';
dbms_output.put_line(v_temp.deptno || ' ' || v_temp.dname);
end;
--PL/SQL裏執行select語句的話,配合into,必須返回並只能返回一條記錄
--SQL語句的運用
declare
v_ename emp.ename%type;
v_sal emp.sal%type;
begin
select ename,sal into v_ename,v_sal from emp where empno = 7369;
dbms_output.put_line(ename || ' ' || v_sal);
end;
declare
v_emp emp%rowtype;
begin
select * into v_emp from emp where empno = 7369;
dbms_output.put_line(v_emp.ename);
end;
declare
v_deptno dept.deptno%type := 50;
v_dname dept.dname%type := 'aaaa';
v_loc dept.loc%type := 'bj';
begin
insert into dept2 values(v_deptno,v_dname,v_loc);
commit;--別忘了!!!
end;
select * from dept2;
declare
v_deptno emp2.deptno%type := 10;
v_count number;
begin
--update emp2 set sal = sal/2 where deptno = v_deptno;
--select deptno into v_deptno from emp2 where empno = 7369;
select count(*) into v_count from emp2;
dbms_output.put_line(sql%rowcount || '條記錄被影響');//sql,關鍵字,代表剛剛執行的sql程序
end;
--PL/SQL執行DDL語句,需要加execute immediate
begin
execute immediate 'create table T(nnn varchar2(20) default ''aaaa'')';
end;
--if語句
--取出7369的薪水,如果<1200,則輸出'low',如果<2000則輸出'middle',否則輸出'high'
declare
v_sal emp.sal%type;
begin
select sal into v_sal from emp where empno = 7369;
if (v_sal<1200) then
dbms_output.put_line('low');
elsif(v_sal<2000) then --elsif沒e
dbms_output.put_line('midddle');
else
dbms_output.put_line('high');
end if;
end;
--循環
declare
i binary_integer := 1;
begin
loop
dbms_output.put_line(i);
i := i + 1;
exit when (i >= 11);
end loop;
end;
declare
j binary_integer := 1;
begin
while j < 11 loop
dbms_output.put_line(j);
j := j + 1;
end loop;
end;
begin
for k in 1..10 loop
dbms_output.put_line(k);
end loop;
for k in reverse 1..10 loop
dbms_output.put_line(k);
end loop;
end;
--錯誤處理
declare
v_temp number(4);
begin
select empno into v_temp from emp where deptno = 10;
exception
when too_many_rows then
dbms_output.putline('太多記錄了');
when others then
dbms_output.put_line('error');
end;
declare
v_temp number(4);
begin
select empno into v_temp from emp where empno = 2222;
exception
when no_data_found then
dbms_output.put_line('沒有數據');
end;
--sql程序跨數據庫平臺較好,PL/SQL效率高
--DBA,錯誤日誌
create table errorlog
(
id number primary key,
errcode number,
errmsg varchar2(1024),
errdate date
);
create sequence seq_errorlog_id start with 1 increment by 1;
declare
v_deptno dept.deptno%type := 10;
v_errcode number;
v_errmsg varchar2(1024);
begin
delete from dept where deptno = v_deptno;
commit;
exception
when others then
rollback;
v_errcode := SQLCODE;
v_errmsg := SQLERRM;
insert into errorlog values (seq_errorlog_id.nextval,v_errcode,v_errmsg,sysdate);
commit;
end;
--遊標cursor,結果集上的指針
declare
cursor c is
select * from emp;--只是聲明遊標,還未取數據
v_emp c%rowtype
begin
open c;
fetch c into v_emp;
dbms_output.put_line(v_emp.ename);
close c;
end;
declare
cursor c is
select * from emp;
v_emp c%rowtype;
beigin
open c;
loop
fetch c into v_emp;
exit when (c%notfound);
dbms_output.put_line(v_emp.ename);
end loop;
close c;
end;
--帶參數的遊標
declare
cursor c(v_deptno emp.deptno%type,v_job emp.job%type)
is
select ename,sal from emp where deptno = v_deptno and job = v_job;
begin
for v_temp in c(30,'clerk') loop
dbms_output.put_line(v_temp.ename);
end loop;
end;
--可更新的遊標
declare
cursor c
is
select * from emp2 for update;
begin
for v_temp in c loop
if(v_temp.sal < 2000) then
update emp2 set sal = sal*2 where current of c;
else if (v_temp.sal = 5000) then
delete from emp2 where current of c;
end if;
end loop;
commit;
end;
--創建存儲過程,帶有名字的PL/SQL塊
grant create procedure to shijin;
create or replace procedure p
is
cursor c is
select * from emp2 for update;
begin
for v_emp in c loop
if(v_emp.deptno = 10) then
update emp2 set sal = sal + 10 where current of c;
else if (v_emp.deptno = 20) then
update emp2 set sal = sal + 20 where current of c;
else
update emp2 set sal = sal + 50 where current of c;
end if;
end loop;
commit;
end loop;
begin
p;
end;
或者
exec p;
--帶參數的存儲過程,默認是in
create or replace procedure p
(v_a in number,v_b number,v_ret out number,v_temp in out number)
is
begin
if (v_a > v_b) then
v_ret := v_a;
else
v_ret := v_b;
end if;
v_temp := v_temp + 1;
end;
declare
v_a number := 3;
v_b number := 4;
v_ret number;
v_temp number := 5;
begin
p(v_a,v_b,v_ret,v_temp);
dbms_output.put_line(v_ret);
dbms_output.put_line(v_temp);
end;
--函數
create or replace function sal_tax
(v_sal number)
return number
is
begin
if(v_sal < 2000) then
return 0.10;
elsif(v_sal < 2750) then
return 0.15;
else
return 0.20;
end if;
end;
select sal_tax(sal) from emp;
--觸發器!!!!牢牢掌握概念
create table emp2_log
(
uname varchar2(20),
action varchar2(10),
atime date
);
grant create triger to shijin;
create or replace trigger trig
after insert or delete or update on emp2 --此處可以加上for each row
begin
if inserting then
insert into emp2_log values (USER,'insert',sysdate);
elsif updating then
insert into emp2_log values (USER,'update',sysdate);
elsif deleting then
insert into emp2_log values (USER,'delete',sysdate);
end if;
end;
update emp2 set sal = sal*2 where deptno = 30;
drop trigger trig;
create or replace trigger trig
after update on dept
for each row
begin
update emp set deptno = :NEW.deptno where deptno = :OLD.deptno;
end;
--樹狀結構數據的存儲與顯示
drop table article;
create table article
(
id number primary key,
cont varchar2(4000),
pid number,
isleaf number(1),--0代表非葉子節點,1代表葉子節點
alevel number(2)
)
create or replace procedure p (v_pid article.pid%type,v_level binary_integer) is
cursor c is select * from article where pid = v_pid;
v_preStr varchar2(1024) := '';
begin
for i in 1..v_level loop
v_preStr := v_preStr || '****';
end loop;
for v_article in c loop
dbms_output.put_line(v_preStr || v_article.cont);
if(v_article.isleaf = 0) then
p(v_articel.id,v_level + 1);
end if;
end loop;
end;
insert into article values (1,'螞蟻大戰大象',0,0,0);
insert into article values (2,'大象被打趴下',1,0,1);
insert into article values (3,'螞蟻也不好過',2,1,2);
insert into article values (4,'瞎 說',2,0,2);
insert into article values (5,'沒 有 瞎 說',4,1,3);
insert into article values (6,'怎 麼 可 能',1,0,1);
insert into article values (7,'怎麼沒有可能',6,1,2);
insert into article values (8,'可能性很大的',6,1,2);
insert into article values (9,'大象進醫院了',2,0,2);
insert into article values (10,'護士是螞蟻',9,1,3);
set serverout on;
begin
p(0,0);
end;
show error;
--展示emp的樹狀結構