Publishing Reports to the Web - Downloads - Oracle

Methodology
20.1.2 Accessing the Data
procedure for operations that cannot be performed using normal SQL (for example, to
create a temporary table or any other form of DDL), and in places where it will be
executed sparingly (for example, in triggers that are only fired once per report).
The primary reason to use the SRW.DO_SQL() built-in procedure is to perform DDL
operations, such as creating or dropping temporary tables. For example, have the
SRW.DO_SQL() built-in procedure to create a table. The table’s name is determined by
a parameter entered in the Runtime Parameter Form.
Example
SRW.DO_SQL (`CREATE TABLE' || :tname ||
`(ACCOUNT NUMBER
NOT NULL PRIMARY KEY, COMP NUMBER (10,2))');
20.1.1.4 Java Stored Procedures
Java stored procedures enable you to implement business logic at the server level;
thereby, improving application performance, scalability, and security. Oracle9i allows
PL/SQL and Java stored procedures to be stored in the database. Typically, SQL
programmers who want procedural extensions favor PL/SQL and Java programmers
who want easy access to Oracle data favor Java. Although Java stored procedures offer
extra flexibility, there is some overhead involved. Balance the trade off between
performance and flexibility based on your individual needs.
Refer to the Oracle9i Java Stored Procedures Developer's Guide for more information on
Java stored procedures.
20.1.1.5 The Java Importer
Although Oracle PL/SQL provides a powerful and productive development
environment, it is sometimes necessary to integrate with external application services
and providers. As many of these external application services and providers are
increasingly offering integration points in Java. Oracle Reports integrates with the
Oracle Java Importer to facilitate the invocation of business logic contained in external
middle-tier Java classes. The Java Importer declaratively creates a PL/SQL wrapper
package for each class you select and exposes the methods identified in the class
through PL/SQL functions and procedures. This allows you to instantiate, use, and
destroy the Java object instances when the report is run. While this powerful extension
insulates you from having to write Java code yourself, there is some overhead
involved. Separate PL/SQL packages are generated for every class specified. The
PL/SQL generator performs type translations when it generates the PL/SQL packages
from the Java methods. Any time a Java object instance is created using the new
function in the PL/SQL package and generated by the Java Importer, the result is
stored in a variable of type JOBJECT. Java Object persistence must be carefully handled
because accumulating large numbers of global references without removing them
increases the JVM’s memory consumption.
If your performance measuring tools show that the report spends a large amount of
time accessing data from the data source(s), you need to review the structure of the
data and determine how the data is being used. Inefficient schema design has a
dramatic affect on the performance of a report. For example, an overly normalized
data model can result in many avoidable joins or queries.
20-8 Oracle Application Server Reports Services Publishing Reports to the Web