1.自定義（顯式）遊標

set serverout on;
declare cursor cu_emp is select empno,ename,sal from emp;
e_no number;
e_name varchar2(10);
e_sal number;
begin
open cu_emp;
fetch cu_emp into e_no,e_name,e_sal;
while cu_emp%found loop --- 遊標存在時
dbms_output.put_line(‘編號：‘||e_no||‘，姓名：‘||e_name||‘，基本薪資：‘||e_sal);
fetch cu_emp into e_no,e_name,e_sal;
end loop;
close cu_emp;
end;

2.應用被遍歷的的表的列類型
set serverout on;
declare cursor cu_emp is select empno,ename,sal from emp;
e_no emp.empno%type; -- empno列的類型
e_name emp.ename%type;
e_sal emp.sal%type;
begin
open cu_emp;
fetch cu_emp into e_no,e_name,e_sal;
while cu_emp%found loop
dbms_output.put_line(‘編號：‘||e_no||‘，姓名：‘||e_name||‘，基本薪資：‘||e_sal);
fetch cu_emp into e_no,e_name,e_sal;
end loop;
close cu_emp;
end;

3.應用被遍歷表的行屬性

set serverout on;
declare cursor cu_emp is select * from emp; -- declare 可以同時聲明多個變量，用分號隔開。
e emp%rowtype;
begin
open cu_emp;
fetch cu_emp into e;
while cu_emp%found loop
dbms_output.put_line(‘編號：‘||e.empno||‘，姓名：‘||e.ename||‘，基本薪資：‘||e.sal);
fetch cu_emp into e;
end loop;
close cu_emp;
end;

4.遊標的遍歷可以加入條件
set serverout on;
declare cursor cu_emp is select * from emp where sal>2000 and sal<3000;
e emp%rowtype;
begin
open cu_emp;
fetch cu_emp into e;
while cu_emp%found loop
dbms_output.put_line(‘編號：‘||e.empno||‘，姓名：‘||e.ename||‘，基本薪資：‘||e.sal);
fetch cu_emp into e;
end loop;
close cu_emp;
end;

5.隱式遊標（系統聲明好的遊標，取名為sql）

隱式遊標的屬性 返回值類型 意 義
SQL%ROWCOUNT 整型 代表 DML 語句成功執行的數據行數
SQL%FOUND 布爾型 值為 TRUE 代表插入、刪除、更新或單行查詢操作成功
SQL%NOTFOUND 布爾型 與 SQL%FOUND 屬性返回值相反
SQL%ISOPEN 布爾型 DML 執行過程中為真，結束後為假

begin
if sql%isopen then
dbms_output.put_line(‘sql遊標已打開‘);
else
dbms_output.put_line(‘sql遊標未打開‘);
end if;
end;

6.隱式遊標的一些方法

declare e_count number;
begin
select count(*) into e_count from emp;
dbms_output.put_line(‘遊標捕獲的記錄數：‘||sql%rowcount);
end;

declare e_count number;
begin
select count(*) into e_count from emp;
dbms_output.put_line(‘遊標捕獲的記錄數：‘||sql%rowcount);
end;

begin
update emp set ename=‘sb3‘ where empno=111;
if sql%rowcount=1 then
dbms_output.put_line(‘已更新‘);
else
dbms_output.put_line(‘未更新‘);
end if;
end;

begin
update emp set ename=‘sb3‘ where empno=111;
if sql%found then
dbms_output.put_line(‘已更新‘);
else
dbms_output.put_line(‘未更新‘);
end if;
end;

7.強類型動態遊標

declare type emptype is ref cursor return emp%rowtype;
cu_emp emptype;
e_count number;
e emp%rowtype;
begin
select count(*) into e_count from emp where job=‘PRESIDENT1‘;
if e_count=0 then
open cu_emp for select * from emp;
else
open cu_emp for select * from emp where job=‘PRESIDENT‘;
end if;
fetch cu_emp into e;
while cu_emp%found loop
dbms_output.put_line(‘編號：‘||e.empno||‘，姓名：‘||e.ename||‘，基本薪資：‘||e.sal);
fetch cu_emp into e;
end loop;
close cu_emp;
end;

8.弱類型動態遊標（更強大）
declare type customType is ref cursor;
e_count number;
e emp%rowtype;
s salgrade%rowType;
cType customType;
begin
select count(*) into e_count from emp where job=‘PRESIDENT1‘;
if e_count=0 then
open cType for select * from salgrade;
fetch cType into s;
while cType%found loop
dbms_output.put_line(‘等級：‘||s.grade||‘，最低薪資：‘||s.losal||‘，最高薪資：‘||s.hisal);
fetch cType into s;
end loop;
close cType;
else
open cType for select * from emp where job=‘PRESIDENT‘;
fetch cType into e;
while cType%found loop
dbms_output.put_line(‘編號：‘||e.empno||‘，姓名：‘||e.ename||‘，基本薪資：‘||e.sal);
fetch cType into e;
end loop;
close cType;
end if;
end;

oracle 遊標