database 初级问题求教# Database - 数据库
m*g
1 楼
'选修'了一们database, 可是脑瓜不济当年啦。。。好多问题不懂的说。
向大虾们请教3个问题先:
1) Why is BCNF a good relational database design objective?
不懂,因为BCNF is said to be optimum ONLY in principle, whilst 3NF is more preferable to
database designer.. :P
2) Why is the relational data model currently more successful than the hierachical data mode?
只是因为他使用primary key 和referential key么?
3) 怎样证明:
if R is in 3NF, and there is a unique key for R (i.e. R has only
one key w.r.t F) 则R is in BCNF?
10G的thanks.. :))))
向大虾们请教3个问题先:
1) Why is BCNF a good relational database design objective?
不懂,因为BCNF is said to be optimum ONLY in principle, whilst 3NF is more preferable to
database designer.. :P
2) Why is the relational data model currently more successful than the hierachical data mode?
只是因为他使用primary key 和referential key么?
3) 怎样证明:
if R is in 3NF, and there is a unique key for R (i.e. R has only
one key w.r.t F) 则R is in BCNF?
10G的thanks.. :))))