DB中的Java类 [英] Java class in DB
问题描述
任何人都可以解释为什么将Java类存储在Db中的想法吗?这有什么用?以及如何使用Java类创建存储过程?
Can anyone explain why was idea to store Java class in Db? What it is good for? And how to create stored procedure with Java class?
最诚挚的问候！
推荐答案
Oracle在版本8i中将存储过程引入了其数据库. i 代表互联网"，就像互联网就绪"一样，这基本上是一种营销.但是Java存储过程允许Oracle通过利用大量可用的Java库来极大地扩展数据库中可用的功能范围. Oracle 8i中的许多新数据库功能是Java库的PL/SQL包装，尤其是XML.
Oracle introduced stored procedures into their database in release 8i. The i stood for "internet", as in "internet-ready", which basically was a bit of marketing. But Java Stored Procedures allowed Oracle to extend the range of functionality available in the database queite dramatically, by leveraging the vast amount of Java libraries available. A lot of the new database functionality in Oracle 8i was PL/SQL wrappers of Java libraries, notably the XML stuff.
Oracle显着地将许多功能重写到Oracle 9的本机C中，因为它的运行速度比包装的Java东西快得多.我知道，喜欢那个.
Significantly Oracle re-wrote a lot of that functionality into native C in Oracle 9, because it ran a lot faster than the wrapped Java stuff. I know, fancy that.
对我们来说，什么时候使用Java存储过程有意义?基本上，当Java提供某些功能时，本机数据库语言不提供这些功能.例如，我编写了JSP来包装ICE Syslog Java类，因此我的PL/SQL日志记录例程可以写入syslog文件.这表明了Java的一个非常普遍的用例-将数据库应用程序的范围扩展到OS中. JSP的最常见用法是编写host命令，该命令允许PL/SQL程序激发外部可执行文件.
For us, when does it make sense to use Java Stored Procedures? Basically, when there features available in Java which are not available in the native database language. For instance, I have written JSPs to wrapper the ICE Syslog java classes, so my PL/SQL logging routines can write to syslog files. This indicates a very common use case for Java - extending the reach of our database applications into the OS. Perhaps the most common use of a JSP is to write a host command which allows a PL/SQL program to fire an external executable.
我认识到一些写JSP的开发人员，因为他们了解Java并且不想学习PL/SQL.这不够好，有两个原因:
I know some developers who write JSPs because they know Java and don't want to learn PL/SQL. This is not good enough for two reason:
- 使用内置组件总比重新发明轮子要好
- 正如我已经提到的，数据库中的Java的性能不如本地代码.
当然，如果您正在苦苦研究必须与几种不同的数据库产品一起运行的产品，那么Java的跨平台适应性将非常吸引人.当涉及到过程语言(T-SQL与PL/SQL等)时，DBMS的不同风格差异最大，因为与SQL不同，它没有标准.
Of course, if you are wroking on a product which has to run against several different database products, then Java's cross-platform adaptability is very appealing. The different flavours of DBMS are most divergent when it comes to their procedural languages (T-SQL vs PL/SQL, etc) because there is no standard for it, unlike SQL.
If you want to learn about writing JSPs in Oracle, the online documentation is a good place to start. If it turns out you are using a different database rather than Oracle, well I'm sure that product has its own equally fine manual.
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