Oracle中的树状展示与储存

[size=medium]树状结构的存储与展示:

drop table article;
	
	create table article
	(
	id number primary key,
	cont varchar2(4000),
	pid number,
	isleaf number(1), --0代表非叶子节点,1代表叶子节点
	alevel number(2)
	);
	
	insert into article values(1,'蚂蚁大战大象',0,0,0);
	insert into article values(2,'大象被打趴下了',1,0,1);
	insert into article values(3,'蚂蚁也不好过',2,1,2);
	insert into article values(4,'瞎说',2,0,2);
	insert into article values(5,'没有瞎说',4,1,3);
	insert into article values(6,'怎么可能',1,0,1);
	insert into article values(7,'怎么没有可能',6,1,2);
	insert into article values(8,'可能性很大',6,1,2);
	insert into article values(9,'大象进医院了',2,0,2);
	insert into article values(10,'护士是蚂蚁',9,1,3);
	cmmmit;

展示树状展示:

	
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
	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.cont);
		if(v_article.isleaf = 0) then
			p(v_article.id,v_level+1);
		end if;
	end loop;
end;

显示出错的信息:show error;

set serveroutput on;

调用存储:exec p(0,0);

SQL> exec p(0,0);
蚂蚁大战大象
----大象被打趴下了
--------蚂蚁也不好过
--------瞎说
------------没有瞎说
--------大象进医院了
------------护士是蚂蚁
----怎么可能
--------怎么没有可能
--------可能性很大

PL/SQL 过程已成功完成。