pl/sql基础语法

--数据定义
--创建表
--drop table scores;
--drop table student;

Create   table student(
Name  varchar2(10)  constraint nname not null ,
No varchar2(3) constraint pk_no primary key  ,
Sex varchar2(4)default '男'
);
create    table scores(
id number constraint pk_ID primary key  ,
no varchar2(3) constraint fp_no references student(no) ,
name  varchar2(100),
num  number
);
--drop table scores;
--drop table student;

--创建视图
create view view_student as select *  from student;
drop view view_student
---创建索引
create index bh on student(no,name);
drop index bh;
---创建约束条件
----ALTER TABLE 表名 ADD(CONSTRAINT 约束名 约束类型(列名))
alter table STUDENT add constraint chk check (sex='男' or  sex= '女');
----alter table 表名  drop(constraint)
alter table student drop   constraint chk

ALTER TABLE scores DISABLE  constraint pk_ID;----关闭  ALTER TABLE student DISABLE/enable CONSTRAINT nn_sname
ALTER TABLE student disABLE CONSTRAINT nname;
ALTER TABLE scores DISABLE constraint fp_no;
ALTER TABLE student DISABLE  constraint nname;
ALTER TABLE student DISABLE   constraint pk_no;
ALTER TABLE student DISABLE  constraint nname;
---添加列  ALTER TABLE products ADD description text;
ALTER TABLE student ADD description varchar2(100);
----删除列   ALTER TABLE products drop description text;
ALTER TABLE student drop column description ;

alter table yw_cyzt_wyqytj add YWFSR number;
comment on column yw_cyzt_wyqytj.ywfsr is '物业费
收入';
alter table yw_cyzt_wyqytj add YWJYSR number;
comment on column yw_cyzt_wyqytj.YWJYSR is '物业经
营收入';
alter table yw_cyzt_wyqytj add QTYWSR number;
comment on column yw_cyzt_wyqytj.QTYWSR is '其他业
务收入';

数据查询
Select *  from  student

数据库操纵
Update  insert  delete
Update table_name
Insert into table_name  values()
Delete table_name

添加数据
declare
icount integer;
sSQL varchar(100);
BEGIN
for icount in 1 ..90 loop
sSQL:='insert into student(name,no)values('||icount ||',' || icount || ');';
dbms_output.put_line(SSQL);
---execute immediate sSQL;
END LOOP;
END;

Sql块
DECLARE
V1 nchar(10);
v_no varchar(3):='1';
BEGIN
SELECT t.name INTO V1  FROM student t WHERE no=v_no;
--SELECT t.name INTO V1  FROM student t
DBMS_OUTPUT.PUT_LINE (v1);
exception
When TOO_MANY_ROWS THEN

DBMS_OUTPUT.PUT_LINE ('More than one manager');
end;

自定义变量
Record类型
declare
type t_re is record
( name1 student.name%type,name2  student.no%type,name3 student.sex%type);
re t_re;
begin
select * into re from student where no=40;
--select * into re from student where no=40;
dbms_output.put_line(re.name1 || ';' || re.name2 || ';' ||re.name3);
exception
when too_many_rows then
DBMS_OUTPUT.PUT_LINE ('More than one manager');
end;

索引表
-- INDEX BY TABLES(不是非/聚簇索引-存在的物理表，它是一个虚拟表)
declare
cursor cur is select *  from student;
type type_arr is table of student%rowtype index  by binary_integer;
arr_tr type_arr;
iCount integer:=1;
begin

for i in cur LOOP
arr_tr(icount):=i;
icount:=icount+1;
END LOOP;

for icount in 1 ..arr_tr.count loop
dbms_output.put_line(arr_tr(icount).name || arr_tr(icount).no || arr_tr(icount).sex );
end loop;
if arr_tr.EXISTS(2)  then
dbms_output.put_line('arr_tr(2)=' || arr_tr(2).name || arr_tr(2).no || arr_tr(2).sex);
end if;
end;

游标变量
显示游标
declare
icount integer:=0;
cursor cur1 is  select *  from student ;---不带参数的游标
cursor cur2(v_no number) is  select *  from student t where to_number(t.no)>v_no;---带参数游标
type type_record is  record (name student.name%type,no student.no%type,sex student.sex%type);
rec_stu type_record;
v_name student.name%type;
v_no student.no%type;
v_sex student.sex%type;
begin

dbms_output.put_line('不带参数的手动打开的游标'  );
open cur1;--
loop
exit when cur1%notfound;
fetch cur1 into rec_stu;

dbms_output.put_line('当前获取的值为：' || rec_stu.name ||rec_stu.no||rec_stu.sex);
end loop;
close cur1;

dbms_output.put_line('带参数的用for打开的游标');
for i in cur2(20)loop
dbms_output.put_line('当前获取的值为：' || i.name ||i.no||i.sex);
end loop;
end;

隐示游标
declare
v_no varchar2(10):=&学号;
--v_no number:=&学号;---为什么在数字时能够正确判断
begin
delete scores t  where t.no=trim(v_no);
--delete scores t  where t.no=v_no;
if sql%notfound  then---found,rowcount,isopen
delete student t1 where t1.no=v_no;
dbms_output.put_line(sql%rowcount);
end if;

end;
游标修改 删除操作
select *  from student;
declare
cursor cur is  select *  from student for update of name nowait;
begin
for i in cur loop
UPDATE student set name='1'  where current of cur;
end loop;
end;
--select *  from student;
流程控制语句
条件语句
---条件语句
--if
declare
v_score number(5,2):=&分数;
v_Result varchar(100):='';
begin
if v_score>0  and v_score<60 then
v_result:='未及格';
elsif v_score<80  then
v_result:='中';
elsif v_score<90 then
v_result:='良';
else
v_result:='优';
end if;
dbms_output.put_line(v_result);
end;

--case
declare
v_score varchar2(4):=&级别;
v_Result varchar(100):='';
begin
case upper(trim(v_score))
when 'D' then
v_result:='未及格';
when 'C' then
v_result:='中';
when 'B' then
v_result:='良';
when 'A' then
v_result:='优';
else
v_result:='未知';
end case;
dbms_output.put_line(v_result);
end;

循环语句
-- for
declare
i number:=0;
j number:=0;
icount number:=10;
str varchar(20):='';
begin
for i in 1.. icount loop
str:='';
for j in  1  .. icount-i loop
str:=str ||'*';
end loop;
dbms_output.put_line(str);
end loop;
end ;

--while循环
declare
cursor cur is select *  from student;
st student%rowtype;
begin
open cur;
dbms_output.put_line('查询的条数:' || cur%rowcount);
loop
exit when cur%notfound;
fetch cur into st;
dbms_output.put_line(st.name ||st.no ||st.sex );
end loop;
close cur;
end;

函数
create or replace function fun_sum return number is
Result number;
begin
select count(*) into Result from student ;
return(Result);
end fun_sum;
-- select  fun_sum  from dual

create or replace function fun_Sum_stu(v_name  varCHAR)
return number is  sun number:=0;
begin
select sum(to_number(no)) into sun from student where name=v_name;
return sun;
end fun_Sum_stu;

存储过程
create or replace procedure pro_find is
result number;
begin
select count(*) into result  from student  ;
end pro_find;

触发器
create or replace trigger tr_out
before update on student
for each row
declare
-- local variables here
begin
dbms_output.put_line('修改前数据：'||:old.name || :old.no || :old.sex);
dbms_output.put_line('修改后数据：'||:new.name || :new.no || :new.sex);
end tr_out;update student set name='12'  where no='2'