life___seven的博客

oracle数据库sql： 1)oracle时间函数： select * from dme_formal.dme_doc_info i where i.app_id='182'and i.created_date between to_date('2015-6-1 00:00:01','yyyy-mm-dd hh24:mi:ss') AND to_date('2015-6-30 23:59...

1NF:字段不可分; 2NF:有主键，非主键字段依赖主键; 3NF:非主键字段不能相互依赖;