oracle 基础知识总结



set serveroutput on

--登陆scott用户

conn scott/root@orcl;

--创建同义词

create synonym MyEmp for scott.emp;

--赋表emp权限给xiaomei

grant all on emp to xiaomei

--登陆用户xiaomei

con scott/root@orcl;

--查询 表MyEmp

select * from MyEmp;

--创建PL/sql 过程

--查看变量值

set serveroutput on;

--根据 := 给变量赋值

declare

sname varchar2(20) default 'jerry';

begin

sname :=sname||' and tom';

dbms_output.put_line(sname);

end;

/

根据select --- into 给变量赋值

declare

sname varchar2(20) default 'jerry';

begin

select ename into sname from MyEmp where empno=7934;

dbms_output.put_line(sname);

end;

/

--申明常量

declare

pi constant number :=3.14;

r number default 3;

area number;

begin

area :=pi*r*r;

dbms_output.put_line(area);

end;

/

--申明宿主变量

/*

var emp_name varchar(30);

begin

select ename into :emp_name from emp where empno=7499;

end;

print emp_name;

*/

--登陆scott

conn scott/root@orcl;

--属性数据类型 %type（列数据） 和%rowtype(一行数据，相当于一个对象)

declare

myemp emp%rowtype;

begin

select * into myemp from emp where empno=7934;

dbms_output.put_line(myemp.ename);

end;

/

declare

sal emp.sal%type;

mysal number(4) :=3000;

totalsal mysal%type;

begin

select sal into sal from emp where empno=7934;

totalsal:=sal+mysal;

dbms_output.put_line(totalsal);

end;

/

--if-then-elseif 应用

declare

newSal emp.sal%type;

begin

select sal into newSal from emp where ename='JAMES';

if newSal>1500 then

update emp set comm=1000 where ename='JAMES';

elsif newSal>1500 then

update emp set comm=800 where ename='JAMES';

else

update emp set comm=400 where ename='JAMES';

end if;

end;

--case 不返回值

declare

v_grade char(1):=upper('&p_grade');

begin

case v_grade

when 'A' then

dbms_output.put_line('Excellent');

when 'B' then

dbms_output.put_line('Very Good');

when 'C' then

dbms_output.put_line('Good');

else

dbms_output.put_line('No such grade');

end case;

end;

--case 返回值

declare

v_grade char(1):=upper('&grade');

p_grade varchar(20);

begin

p_grade :=

case v_grade

when 'A' then

'Excellent'

when 'B' then

'Very Good'

else

'No'

end;

dbms_output.put_line('Grade:'||p_grade);

end;

--搜索sase

declare

v_grade char(1):=upper('&grade');

p_grade varchar(20);

begin

p_grade :=

case

when v_grade='A' then

'Excellent'

when v_grade='B' then

'Good'

else

'NO'

end;

dbms_output.put_line('Grade:'||p_grade);

end;

--loop循环

declare

counter number(3):=0;

sumResult number:=0;

begin

loop

counter:=counter+1;

sumResult:=sumResult+counter;

if counter>=100 then

exit;

end if;

end loop;

dbms_output.put_line('result is:'||to_char(sumResult));

end;

--while循环

declare

counter number(3):=0;

sumResult number:=0;

begin

while counter<100 loop

counter :=counter+1;

sumResult:=sumResult+counter;

end loop;

dbms_output.put_line('restule is:'||sumResult);

end;

--for 循环

declare

counter number(3):=0;

sumResult number:=0;

begin

for counter in 1..100 loop

sumResult:=sumResult+counter;

end loop;

dbms_output.put_line('result is:'||sumResult);

end;

--goto 和 null

declare

sumsal emp.sal%type;

begin

select sum(sal) into sumsal from emp;

if sumsal>2000 then

goto first_label;

else

goto second_label;

end if;

<<first_label>>

dbms_output.put_line('above 20000:'||sumsal);

<<second_label>>

NULL;

end;

--异常raise_application_error(异常码,异常信息);

declare

sal emp.sal%type;

myexp exception;

begin

select sal into sal from emp where ename='JAMES';

if sal<5000 then

raise myexp;

end if;

exception

when NO_DATA_FOUND THEN

dbms_output.put_line('no');

when myexp then

raise_application_error(-20001,'sal is to less!');

end;

/