According to these work , we design and develop database grid prototype system called griddaen - dai . it adopts java mechanism and integrates database resources in internet , provides uniform logical data views and data access service for grid user at different places . this system mainly adopts multi - domain server mechanism and server - registration mechanism , provides uniform access to many heterogeneous database resources , and has features such as dynamic configuration and scalability . the system is composed of metadata information service ( mis ) , data access service ( das ) , clients and the low - level distributed heterogeneous database resources Griddaen - dai利用java平台无关特性,整合广域环境下分布异构的数据库资源为地理上分布的用户提供了全局的逻辑数据视图和统一的数据访问服务;系统采用分布、独立的多域服务器技术和服务器注册机制,支持对多种异构数据库资源的统一访问,具有动态配置和可扩展性等特征,系统在逻辑结构上主要有元服务、数据访问服务、客户端和底层分布异构的数据库资源等部分组成。
In my opinion , in early song dynasty or wudaishiguo period there ' s long dao with 3f blade and 1f hilt . by the law of ming dynasty the high - class swords were given to officials , the mid - class were used handed in to yuan forces , and the low - class were destoryed 愚见，在宋初或五代十国己有刃三尺柄一尺之长刀，或宋神宗时大量作兵备而己，元尽灭宋及以前刀剑，明令上等刀剑悉输于官，中等缴与元军使用，下等悉皆销毁，有元一代，乃汉族兵器及武术之大浩劫禁武毁兵器时期，今人须在日本重睹宋以前宝刀之精美。
