一, 表

create table article
(
    id number primary key,
    cont varchar2(4000),
    pid number,
    isleaf number(1),   -- 0, 葉子結點; 1, 非葉子結點
    alevel number(2)
);

二, 資料

insert into article values(1, '螞蟻大戰大象', 0, 0, 0);
insert into article values(2, '大象被打趴下了', 1, 0, 1);
insert into article values(3, '螞蟻也不好過', 2, 1, 2);
insert into article values(4, '瞎說', 2, 0, 2);
insert into article values(5, '沒有瞎說', 4, 1, 3);
insert into article values(6, '怎麼可能', 1, 0, 1);
insert into article values(7, '怎麼沒有可能', 6, 1, 2);
insert into article values(8, '可能性是很大的', 6, 1, 2);
insert into article values(9, '大象進醫院了', 2, 0, 2);
insert into article values(10, '護士是螞蟻', 9, 1, 3);
 

三, 樹狀結構

四, 使用儲存過程 展示

create or replace procedure p
    (v_pid article.pid%type, v_level binary_integer)
is
    cursor c is select * from article where pid = v_pid;
    v_preStr varchar2(1024) := '';
begin
    -- 縮排
    for i in 1..v_level loop
        v_preStr := v_preStr || '*   ';
    end loop;


    for v_article in c loop
        dbms_output.put_line(v_preStr || v_article.id || '-' || v_article.cont || '=>' || v_article.pid);
        -- 如果不是葉子結點, 則遞迴
        if (v_article.isleaf = 0) then
            p (v_article.id, v_level + 1);
        end if;
    end loop;
end;
 

SQL> exec p(0,0);
1-螞蟻大戰大象=>0
*   2-大象被打趴下了=>1
*   *   3-螞蟻也不好過=>2
*   *   4-瞎說=>2
*   *   *   5-沒有瞎說=>4
*   *   9-大象進醫院了=>2
*   *   *   10-護士是螞蟻=>9
*   6-怎麼可能=>1
*   *   7-怎麼沒有可能=>6
*   *   8-可能性是很大的=>6