-- 循環(huán)輸出數(shù)值
begin
  for i in 1 .. 100 loop
    sys.dbms_output.put_line(i);
  end loop;
end;

-- 循環(huán)累加
declare
  var_sum number := 0;
begin
  for i in 1 .. 100 loop
    var_sum := var_sum + i;
  end loop;
  sys.dbms_output.put_line(var_sum); -- 5050
end;

-- 批量插入
begin
  for i in 1 .. 100 loop
    -- todo: insert into some_table(field1, field2, ..., fieldN) values(valie1, value2, ..., valueN);
    sys.dbms_output.put_line('insert: ' || to_char(i));
  end loop;
  commit;
  sys.dbms_output.put_line('多次insert,統(tǒng)一commit');
end;

-- 批量更新
begin
  for i in 1 .. 100 loop
    -- todo: update some_table set fieldN = valueN where fieldN = valueN;
    sys.dbms_output.put_line('update: ' || to_char(i));
  end loop;
  commit;
  sys.dbms_output.put_line('多次update,統(tǒng)一commit');
end;

-- 查詢你能管理的所有用戶信息
select user_id, username, created from all_users;

-- 循環(huán)輸出用戶表信息
begin
  for cur_row in (select user_id, username, created from all_users) loop
    sys.dbms_output.put_line(cur_row.username);
  end loop;
end;
-- 當(dāng)循環(huán)對(duì)象是比較長(zhǎng)串的SQL時(shí),建議提取游標(biāo),方便后續(xù)查看和維護(hù)

-- 循環(huán)輸出用戶表信息(游標(biāo)提取)
declare
  -- 提取游標(biāo)對(duì)象,方便單獨(dú)維護(hù)SQL
  cursor cursor_all_users is
    select user_id, username, created from all_users;
  -- 游標(biāo)子項(xiàng)(更多的時(shí)候,表是動(dòng)態(tài)表,所以這句聲明也可以省略)
  -- cursor_user all_users%rowtype;
begin
  for cursor_user in cursor_all_users loop
    dbms_output.put_line(cursor_user.username);
  end loop;
end;