NonStop Server for Java (NSJ) Programmer's Guide (NSJ 2.0+)

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Java Naming and Directory Interface (JNDI)

Highlights

The Java Naming and Directory Interface

(JNDI) provides naming and directory functionality to Java programs. It is

independent of any specific directory service implementation; therefore, it allows a variety of directories to be accessed in a

common way.

The JNDI architecture consists of an Application Programming Interface (API) and a Service Provider Interface (SPI). Java

programs use the JNDI API to access a variety of naming and directory services. The JNDI SPI enables a variety of naming

and directory services to be plugged in transparently, allowing Java programs that use the JNDI API to access their services.

JNDI is a Java Standard Extension.

NonStop

Server for Java implements JNDI by means of CORBA naming (COS Naming). Compaq NonStop

EJB provides

a COS Naming Service for JNDI.

For more information about the JNDI, see the Sun Microsystems JNDI document

(http://java.sun.com/products/jndi/javadoc/overview-summary.html).

Enhancements for JDBC

2.0

Sun Microsystems has enhanced JDBC

for version 2.0, dividing those enhancements into two parts: the JDBC 2.0 Core API

and the JDBC 2.0 Standard Extension API. This Programmer's Guide briefly describes these enhancements. For a detailed

description of the enhancements, see the Sun Microsystems JDBC documentation

(http://java.sun.com/products/jdk/1.2/docs/guide/jdbc/index.html).

Core Enhancements

The following enhancements have been made to the core API of JDBC 2.0.

Result Set Enhancements

The following describes the new functionality that has been added to JDBC result sets. The goal of the enhancements is to add

two new basic capabilities to result sets: scrolling and updatability.

Scrolling

The JDBC 1.0 API provided one type of result set: forward-only. The JDBC 2.0 API provides three result set types:

forward-only, scroll-insensitive, and scroll-sensitive. The two new result set types support scrolling, but they differ in their

ability to make changes visible while the result set is open. A scroll-insensitive result set provides a static view of the

underlying data it contains (that is, the membership, order, and column values for rows are fixed when the result set is created).

A scroll-sensitive result set is sensitive to underlying changes that are made while the result set is open (that is, changes in the

underlying column values of rows are visible).

Support of the new result set types is optional for a JDBC driver. You can call the method

DatabaseMetaData.supportsResultSetType() to see which result set types are supported by a JDBC driver. An

application can still make a request to a JDBC driver to create a Statement, PreparedStatement, or

CallableStatement object by using a result set type that the driver does not support. In this case, the driver issues a

SQLWarning on the Connection that produces the statement and chooses an alternative value for the result set type of the

statement.

Because Compaq NonStop

SQL/MP does not support scrollable cursors, NonStop

Server for Java does not support

scroll-sensitive result sets. NonStop

Server for Java supports scroll-insensitive result sets by storing the entire result set in

memory. For this reason, if you select a large scroll-insensitive result set, performance can be affected.

With JDBC 2.0, both Statements and PreparedStatements can be created that generate scroll-insensitive result sets.