由于在ORM和现代数据访问方面落后,我希望摆脱DataSets (颤抖),进入一个合适的映射框架。对于旧式sql和数据集,您的sql查询显然只返回所需的数据。我还了解到,L2S还足够聪明地计算其where子句,以便它只返回所请求的对象。NHibernate是一样的吗?艾因德的Linq到NHibernate也是这样吗?Select * from customers where name = "fred"
它会把每一个客户带到内存中,然后过滤
假设我有一个表,其中包含一些键、帐户和点击数。SELECT key, accounts, hits,1.0*hits/accounts as ratio FROM SELECT key, COUNT(DISTINCT accounts) as accounts, SUM(hits) as hits GROUP BY key或
SELECT key, COUNT(DISTINCT accounts) as accounts, SUM(h