正在加载图片...
What Happens When a View Is Used? O The DBMS starts by interpreting the query as if the view were a base table. Typical DBMS turns the query into something like relational algebra. OThe queries defining any views used by the query are also replaced by their algebraic equivalents,and spliced into"the expression tree for the query. 66 What Happens When a View Is Used? zThe DBMS starts by interpreting the query as if the view were a base table. – Typical DBMS turns the query into something like relational algebra. zThe queries defining any views used by the query are also replaced by their algebraic equivalents, and “spliced into ” the expression tree for the query
<<向上翻页向下翻页>>
©2008-现在 cucdc.com 高等教育资讯网 版权所有