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Storing Hierarchical Data in a Database, Part 3

Automating the Tree Traversal Now that you’ve seen some of the handy things you can do with this table, it’s time to learn how we can automate the creation of this table. While it’s a nice exercise the first time and with a small tree, we really need a script that does all this counting and tree walking for us. Let’s write a script that converts an adjacency list to a modified preorder tree traversal...

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Getting Control of the Oracle Java Virtual Machine - Page 4

JVM Operational Test The DBA should check the JVM core functionality before developers and end users begin work. For a test we are going to create a Java class, compile it, load it in the database and execute it as a part of PL/SQL block. Creating Java class: # vi dbatest.java public class EchoInput { public static void main (String[] args){ for (int i=0; i<args.length;i++) ...

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Getting Control of the Oracle Java Virtual Machine - Page 2

Java Virtual Machine Parameters There are four parameters, which directly control the JVM: Shared_pool_size is thememory used by the class loader during the loading and resolving Java classes (jars). Shared Pool memory requirements for class load are 8KB per class. The Java load procedure (initjvm.sql) loads quite large number of the classes so recommended settings for shared_pool_size is around 50MB. Java_pool_size parameter...

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Getting Control of the Oracle Java Virtual Machine - Page 7

Java Backup A good backup is always a DBA's best friend, especially when the database has a large number of Java Classes, Java Resources, Java Grants and Policies. No special tool is provided by Oracle to handle the Java objects backup, you'll need to use standard utilities. A Java Classes Backup is made by a full database export without rows. Example of a full database export: % exp userid=system full=y ROWS=N...

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Getting Control of the Oracle Java Virtual Machine

From time to time, DBAs have to take over "alien" databases. These databases are usually living parts from some failed project, a badly documented job from a previous DBA or in a worst case scenario, a database with very important data without any support. The situation gets worse when the database has the Java Option installed. In this article, I'll explain about the Oracle database Java Option and offer some practical tips...