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oracle复习笔记之PL/SQL程序所要了解的知识点(3)

时间:2014-08-23 11:24来源:网络整理 作者:网络 点击:
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或者使用记录再优化一下: declaretype emp_record is record(v_empid employees.employee_id%type,v_lastName employees.last_name%type,v_sal employees.salary%type);v_emp_record emp_record;cursor

或者使用记录再优化一下:

declare
type emp_record is record(
v_empid employees.employee_id%type,
v_lastName employees.last_name%type,
v_sal employees.salary%type
);
v_emp_record emp_record;
cursor emp_sal_cursor is select employee_id,last_name,salary from employees where 
department_id = 80;
begin 
open emp_sal_cursor;
fetch emp_sal_cursor into v_emp_record;
while emp_sal_cursor%found loop
dbms_output.put_line('employee_id:'||v_emp_record.v_empid||', '||'last_name:'|| 
v_emp_record.v_lastName||', '||'salary:'||v_emp_record.v_sal);
fetch emp_sal_cursor into v_emp_record;
end loop;
close emp_sal_cursor;
end; 

可以使用for循环最优化:(注意:在for循环中它会自动的打开游标、提取游标,当提取完里面的数据后也会自动
的关闭游标

declare
cursor emp_sal_cursor is select employee_id,last_name,salary from employees where 
department_id = 80;
begin 
for c in emp_sal_cursor loop
dbms_output.put_line('employee_id:'||c.employee_id||', '||'last_name:'||c.last_name||', 
'||'salary:'||c.salary);
end loop;
end;


利用游标,调整公司中员工的工资:
工资范围            调整基数
0 - 5000              5%
5000 - 10000       3%
10000 - 15000     2%
15000 -               1%
实现:

declare 
  cursor emp_cursor is select employee_id,salary from employees;
  v_empid employees.employee_id%type;
  v_sal employees.salary%type;
  v_temp number(4,2);
begin 
  open emp_cursor;
  fetch emp_cursor into v_empid,v_sal;
  while emp_cursor%found loop
   if v_sal < 5000 then v_temp:=0.05;
   elsif v_sal < 10000 then v_temp:=0.03;
   elsif v_sal < 15000 then v_temp:=0.02;
   else v_temp:=0.01;
   end if;
  dbms_output.put_line(v_empid||','||v_sal);
  update employees
  set salary = salary * (1+v_temp)
  where employee_id = v_empid;
  fetch emp_cursor into v_empid,v_sal;
  end loop;
  close emp_cursor;
end;

用for循环实现

declare 
  cursor emp_cursor is select employee_id,salary from employees;
  v_temp number(4,2); 
begin 
  for c in emp_cursor loop
   if c.salary <5000 then v_temp:=0.05;
   elsif c.salary <10000 then v_temp:=0.03;
   elsif c.salary <15000 then v_temp:=0.02;
   else v_temp:=0.01;
  end if;
  update employees
  set salary = salary * (1+v_temp)
  where employee_id = c.employee_id;
  end loop;
end;

隐式游标:更新员工salary(涨工资10),如果该员工没有找到,则打印“查无此人”信息:

begin 
  update employees
  set salary = salary + 10
  where employee_id = 1001;
   if sql%notfound then dbms_output.put_line('查无此人');
   end if;
end;

异常:
预定义异常:(有24个预定义异常,可查表

declare
  v_sal employees.salary%type;
begin 
  select salary into v_sal from employees 
  where employee_id > 100;
  dbms_output.put_line(v_sal); 
exception
  when too_many_rows then dbms_output.put_line('输出的行数过多');
  when others then dbms_output.put_line('出现其它的异常了');
end;
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