--遞歸，樹狀結(jié)構(gòu)的存儲(chǔ)與展示
drop table article;
create table article
(
id number primary key,
count varchar2(4000),
pid number,
isleaf number(1), --0 代表非葉子節(jié)點(diǎn)，1代表葉子節(jié)點(diǎn)
alevel number(2)
);
insert into article values(1,'螞蟻大戰(zhàn)大象',0,0,0);
insert into article values(2,'大象被打趴下',1,0,1);
insert into article values(3,'螞蟻也不好過(guò)',2,1,2);
insert into article values(4,'瞎說(shuō)',2,0,2);
insert into article values(5,'沒有瞎說(shuō)',4,1,3);
insert into article values(6,'怎么可能',1,0,1);
insert into article values(7,'怎么沒有可能',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(jìn)醫(yī)院了',2,0,2);
insert into article values(10,'護(hù)士是螞蟻',9,1,3);
commit;
螞蟻大戰(zhàn)大象
大象被打趴下了
螞蟻也不好過(guò)
瞎說(shuō)
沒有瞎說(shuō)
大象進(jìn)醫(yī)院了
護(hù)士是螞蟻
怎么可能
怎么沒有可能
可能性是很大的
--用存儲(chǔ)過(guò)程展現(xiàn)樹狀結(jié)構(gòu)。
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
for i in 0..v_level loop
v_preStr := v_preStr || '****';
end loop;
for v_article in c loop
dbms_output.put_line(v_preStr ||v_article.cont);
if(v_article.isleaf=0) then
p(v_artile.id,v_levle +1);
end if;
end loop;
end;