Plotting one object-db what selfmade by xml+db for sectionbase

I want to plot the next works in priority level so as to make my loads to be lightest.As for the major issue, I should develop the Clinlic, Blog, application/invitation module, the charge module, and PhysicalExm module, etc, going along with the modules, I should have to refit the sections from xml to database sooner or later, by the reasons of two:1. as long as the sections grown up more than twenty, it will be difficult to manage by xml; 2. as long as more and more stuffs were added in the xml, the memory will has been contented by ramdon use things, it is not my want, however, so far I use the xml instead of the database was want to have a try that the xml can decrease the mass working for one relations object module, and I feel that the xml combined with database can make easy for myself for one customer made OR object database. Sounds excitly for me. however, the work could took time for two or three days:the first, I need to make the table relationsip cleary; and build up the tables. What difference between one object-oriented database designed and one normal database designed? I think, the most import point is that the object-oriented designed it start from the toppest object and reference the sub-contents by itself, and ,on the other way, the normal designed, the system has to iterate the database by outer-key to find out whats subcontent belonged to this object.seems I have made it. According on this view, the modification to one xml object -> db/xml, I should buildup several table to store the types of class irrelerantly, and the digester rules must to be changed,too. And another interface to administate this sections change has to be develop, and, at last, I should extends some program to replant the current setting into database. The last problem that, How long this work will take? the closely issue is to build up the clincs in hzw, and has no relationship with the sectionsbase, and, the A/I net should probably work with shadow sections, so, the sections base modifycation should be ahead of the A/I