grails里面有实现树型结构的功能吗？

Start with...Connect By子句递归查询一般用于一个表维护树形结构的应用。创建示例表：CREATE TABLE TBL_TEST
(
ID NUMBER,
NAME VARCHAR2(100 BYTE),
PID NUMBER DEFAULT 0
);插入测试数据：INSERT INTO TBL_TEST(ID,NAME,PID) VALUES('1','10','0');
INSERT INTO TBL_TEST(ID,NAME,PID) VALUES('2','11','1');
INSERT INTO TBL_TEST(ID,NAME,PID) VALUES('3','20','0');
INSERT INTO TBL_TEST(ID,NAME,PID) VALUES('4','12','1');
INSERT INTO TBL_TEST(ID,NAME,PID) VALUES('5','121','2');从Root往树末梢递归select * from TBL_TEST
start with id=1
connect by prior id = pid从末梢往树ROOT递归select * from TBL_TEST
start with id=5
connect by prior pid = id
作者Blog：http://blog.csdn.net/54powerman/找到更全面的资料

create table NR.TEST
(
ID NUMBER not null,
NAME VARCHAR2(50) not null,
PARENTID NUMBER not null
)
select * from TEST START WITH parentid=0 connect by prior id = parentid