（笔记）如何声明使用cursor及其属性

Defined cursor ;

cursor mycursor is select * from employees where employees.salary>tempsal;

 

Learning point on cursor;

declare
tempsal employees.salary%type;
cursor mycursor is select * from employees where employees.salary>tempsal;
currecord employees%rowtype;                             
begin
tempsal:=800;
open mycursor;                                            
if mycursor%isopen then                                   
fetch mycursor into cursorrecord;                         
dbms_output.put_line(to_char(cursorrecord.deptno));
else dbms_output.put_line('游标没有打开');
end if;
end;

    currecord is record type(记录类型)

 

%isopen

if mycursor%isopen then                                   
fetch mycursor into cursorrecord;                         
dbms_output.put_line(to_char(cursorrecord.deptno));
else dbms_output.put_line('游标没有打开');
end if;

 

%found

if mycursor%found then                                  
fetch mycursor into cursorrecord;
dbms_output.put_line(to_char(cursorrecord.deptno));
else dbms_output.put_line('游标没有打开');
end if;

 %rowcount

dbms_output.put_line(to_char(mycursor%rowcount));

 

 loop exit when mycurcor%notfound;

 fetch mycursor into cursorrecord;

 end loop;

declare
tempsal employees.salary%type;
cursor mycursor is select * from employees where employees.salary>tempsal;
currecord employees%rowtype;                             
begin 
tempsal:=800;
open mycursor; 
loop exit
when mycursor%notfound;
fetch mycursor into currecord;
dbms_output.put_line(to_char(currecord.email)) ;
end loop;
end;

 output:

empid=13
empid=10
empid=12
empid=12

 

corrected SQL code:

declare
temp_salary employee.salary%type;
temp_emp employee%rowtype;
cursor mycursor is 
select * from employee where employee.salary>temp_salary;
begin
temp_salary:=2000;
open mycursor;
loop 
fetch mycursor into temp_emp;
exit when mycursor%notfound;
dbms_output.put_line('empid='||temp_emp.empid);
end loop;
end;

 output:

empid=13
empid=10
empid=12

 

declare中声明一个可以承载 mycursor的记录型数据

              声明一个cursor

此处注意：loop exit之间的循环问题

 

在存储过程中使用游标

create or replace procedure emp_pro_cur    
as  
cursor cur is select * from employee where employee.empname like 'd%';   
begin    
  for emp in cur loop  --这里for循环，不需要使用fetch移动游标指针，也不需要open cursor&close cursor  
    dbms_output.put_line(emp.empname);   
    end loop;   
    end;   
--调用存储过程   
call emp_pro_cur();