摘要:
Dom4j and Sax difference。Dom4j 解析的速度慢,而且消耗内存,因为在解析之前要先把文件放到内存中。并采用基于对象的模型解析 有以下几点: 1. Dom4J parse loads the entire XML file into memory before parsi... 阅读全文
摘要:
这有两个语句,可是这两个语句的结果相同,但其他方面有什么区别呢?1.select count(ts.tid),ts.tid from t_s ts ,(select tid from teacher where age12 group by sid)group by ts.tid;2.select ... 阅读全文