%0 Journal Article
%T Bitemporal relational algebra with temporal variables based on BCDM<br>基于BCDM的含有变量的双时态关系代数研究*
%A WANG Lu-bang
%A QIAN Xing-san
%A <br>王路帮
%A 钱省三
%J 计算机应用研究
%D 2010
%I 
%X In BCDM (bitemporal conceptual data model), the valid time variable Now and the transaction time variable UC resolved the problem about the frequent temporal record update. But the existence of temprol variables brought some unsertainty, even wrong on database operations, as well as the temprol relational algebra operations. Based on BCDM, binded the temporal variables, then defined the temporal relational by using the temporal mapping set, at last, established the temporal relational algebra system. The algebra system is close under the bitemporal operation.
%K BCDM
%K bitemporal database
%K temporal variables
%K bitemporal relational algebra<br>双时态概念数据模型
%K 双时态数据库
%K 时态变量
%K 双时态关系代数
%U http://www.alljournals.cn/get_abstract_url.aspx?pcid=5B3AB970F71A803DEACDC0559115BFCF0A068CD97DD29835&cid=8240383F08CE46C8B05036380D75B607&jid=A9D9BE08CDC44144BE8B5685705D3AED&aid=CFE499F4AD721660E4ED66544CFAA896&yid=140ECF96957D60B2&vid=DB817633AA4F79B9&iid=B31275AF3241DB2D&sid=6E3B915514BCF8E8&eid=2C44BAF8BCD26B57&journal_id=1001-3695&journal_name=计算机应用研究&referenced_num=0&reference_num=20