发布于 2014-08-28 00:23:49 | 140 次阅读 | 评论: 0 | 来源: 网友投递
Apache Derby 开源数据库管理系统
Apache Derby是Apache软件基金会所研发的开放源码数据库管理系统；由于Derby是一个纯Java程式，因此只需要操作系统支援Java虚拟机，Derby便可执行。
Apache Derby 10.11.1.1 发布，此版本现已提供下载，更新内容如下：
* MERGE statement - MERGE is a single, join-driven statement which INSERTs, UPDATEs, and DELETEs rows. * Deferrable constraints - Constraint enforcement can now be deferred, typically to the end of a transaction. * WHEN clause in CREATE TRIGGER - An optional WHEN clause has been added which determines which rows fire a trigger. * Rolling log file - The Derby diagnostic log can now be split across a sequence of files. * Experimental Lucene support - Derby text columns can now be indexed and queried via Apache Lucene. * Simple case expression - The "simple" and "extended" syntax for CASE expressions has been added. * Better concurrency for identity columns - The concurrency of identity columns has been boosted. * New ij HoldForConnection command - A new ij command has been added to change the default cursor holdability. * Standard syntax for altering column nullability - Standard syntax has been added for altering the nullability of columns.
Apache Derby是Apache软件基金会所研发的开放源码数据库管理系统；由于Derby是一个纯Java程式，因此只需要操作系统支援Java虚拟机，Derby便可执行。
Derby是特别地为Java环境进行优化，Derby本身不仅是一个纯Java程式，而且Derby在执行用户的SQL程式时，能够把SQL编译成Java bytecode并以系统的Java虚拟机执行。由于SQL程式转成的Java bytecode能被JIT动态翻译，因此Derby可能比传统的数据库管理系统更佳的性能。
其他特性包括：
支援 主从架构 或 嵌入 环境
多线程
ACID
Java数据库连接 (JDBC)
低系统需求：约占 2 MB 的硬盘空间，压缩后更只是600KB