摘要：
Query Optimization 阅读全文
摘要：
Integrity Constraints Motivation To ensure that changes (made by authorized users) to the database do not cause a loss of consistency Constraints are 阅读全文
摘要：
File Organization and Indexing Disk Storage Devices Secondary storage device for high storage capacity and low cost. Data stored as magnetized areas o 阅读全文
摘要：
Transactions and Concurrency Control 事务(Transactions) 根据维基百科的定义，一个数据库事务通常包含了一个序列的对数据库的读/写操作。它的存在包含有以下两个目的：1）为数据库操作序列提供了一个从失败中恢复到正常状态的方法，同时提供了数据库即使在异常状 阅读全文