用两个数据表用树型结构怎样表示?t_unit结构:
unit_code    unit_name                                
------------ ----------- 
450422107    XX镇                        
450422107020 社区居委会                          
450422107200 1村委会                              
450422107201 2村委会                              
450422107202 3村委会                              
450422107203 4村委会                              
450422107204 5村委会                              
450422107205 6村委会 
                             
t_address结构:
4504221072000001 车面一组                                
4504221072000002 车面二组                                
4504221072000003 车面三组                                
4504221072000004 车面四组                                
4504221072000005 车面五组                                
4504221072000006 车面六组                                
4504221072000007 文田组                                  
4504221072000008 文兴组                                  
4504221072010001 一村一组                                
4504221072010002 一村二组                                
4504221072010003 一村三组                                
4504221072010004 一村四组                                
4504221072010005 地方垌组                                
4504221072020001 石村一组                                
4504221072020002 石村二组                                
4504221072020003 石村三组                                
4504221072030001 加坪坡一组                              
4504221072030002 加坪坡二组                              
4504221072030003 思兰一组                                
4504221072030004 思兰二组                                
4504221072030005 思兰三组                                
4504221072030006 思兰四组                                
4504221072030007 大湾组                                  
4504221072030008 冲足组                                  
4504221072030009 哈塘组                                  
4504221072040001 罗平一组                                
4504221072040002 罗平二组                                
4504221072040003 罗平三组                                
4504221072040004 罗平四组                                
4504221072040005 村平组                                  
4504221072040006 大容组                                  
4504221072040007 埌口里组                                
4504221072050001 麦地一组                                
4504221072050002 麦地二组                                
4504221072050003 麦地三组                                
4504221072050004 麦地四组                                
4504221072050005 猫头组                                  
4504221072050006 良村组                                  
4504221072050007 云藤组                                  
4504221072060001 大桥一组                                
4504221072060002 大桥二组                                
4504221072060003 大桥三组                                
4504221072060004 大桥四组                                我在网上查了都是一个表建树的,没有两个表建树,由于不能改动原有的数据结构,有这样的数据怎样建成下面树型结构
----------------------------------------------
450422107    XX镇  
|---450422107020 社区居委会
|------4504221072000001 车面一组                                
|------4504221072000002 车面二组                                
|------4504221072000003 车面三组
|------......
|------......                               
|---450422107200 1村委会
|------4504221072010001 一村一组                                
|------4504221072010002 一村二组                                
|------4504221072010003 一村三组  
|------......
|------......