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CONNX JDBC Driver
JDBC is Sun Microsystems’ JavaSoft application programming
interface (API) standard for connecting to databases that support Structured Query
Language (SQL). JDBC is patterned as a package of object-oriented objects that
include Connect, ResultSet, and Statement. Each object contains various API methods,
for example, Connect(), DisConnect(), and PrepareSQL().
The CONNX JDBC driver implements the JDBC specification developed for use within
CONNX to enable connectivity to all types of databases. Used with the CONNX Data
Dictionary (CDD), the JDBC driver provides a means of using many popular querying
tools and application development tools. The CONNX JDBC driver works with
JDBC-compliant software, which increases its flexibility when used by companies
with a wide range of front-end applications and database types. The CONNX JDBC
interface enables applications to access data in database management systems using
the JavaSoft JDBC API to connect to the databases.
JDBC Driver Architecture
The four types of JDBC drivers are as follows:
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Type 1 - ODBC Bridge
Used with databases that are unable to directly support JDBC. ODBC is a
Microsoft Windows interface to SQL. This solution works best on a
Windows-based system, but may not work on other operating systems that
do not support ODBC.
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Type 2 - Native API, Native Code
The fastest JDBC driver, written partly in Java and partly in native code,
for example, Microsoft C++ . Although it speaks the native protocol of the
SQL database, it is limited to operating systems on which native code is
preinstalled on client machines.
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Type 3 - Net Protocol, Pure Java
Written entirely in Java. This type of driver can run on any platform or
browser that supports Java. The driver converts requests into a database that
uses vendor-neutral protocol. A server process receives the requests and carries
out the specified action on the database. With this type of driver, you can
access SQL databases on different client machines without loading additional
JDBC drivers. This JDBC driver is small and loads quickly.
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Type 4 - Native Protocol, Pure Java
The fastest way to use the Web from a single server. This type of JDBC
driver is written entirely in Java, which means it can be safely loaded
into any Java-powered Web browser. The driver speaks DBMS-vendor-specific
protocol directly to the SQL server. It is efficient, but if you need to
attach to various types of SQL databases, several JDBC drivers must be
loaded onto the client machines.
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CONNX JDBC is a Type 3 driver, which means it can be
run on any platform that supports Java. It is a pure Java implementation,
designed to take advantage of the CONNX architecture.
CONNX JDBC Driver Architecture
The architecture of the CONNX JDBC Driver has four
components:
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CONNX JDBC (Thin Client) Driver
The CONNX JDBC driver is located in a Java .jar file named connxjdbc.jar.
The JDBC driver is a thin JDBC driver that communicates to the CONNX JDBC
Server through the use of a socket. JDBC calls are translated to socket
requests to which the CONNX JDBC Server responds.The .jar file must be
copied to Java Virtual Machine (JVM) platforms other than Windows.
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CONNX JDBC Server
The CONNX JDBC server component is a Microsoft Windows server component
that communicates with the CONNX JDBC driver. It resides on the machine on
which CONNX is installed. It is a Windows executable that opens a socket and
listens for new connections. When it accepts a new connection, it creates a
new thread that is dedicated to communicating to that client. Installing the
CONNX JDBC server component on every machine is an optional task since only
one server is required for communication with all CONNX JDBC client machines.
During installation, CONNX JDBC verifies that the target system is running on
Windows NT. If it is a Windows NT system, the CONNX JDBC Server is installed
as a Windows NT Service, which starts when the system is started. If the target
machine is not a Windows NT machine, the user is prompted to place CONNX JDBC
in the Windows Startup folder.
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CONNX JDBC Router
The CONNX JDBC Router is a Java application placed on the non-Windows
Web server. It is stored in the ConnxRouter.jar file which is located
in C:/ CONNX32/CONNXJDBC/java/jar
The CONNX JDBC Router must be run on the machine that hosts a Web server
but does not have CONNX installed.
If JDBC applets are used in the following environments, a CONNX JDBC Router
must be used:
Non-Windows Web servers (Linux, Solaris, HP-UX)
Windows Web servers running on a system on which
CONNX is not installed.
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CONNX DSN Registry Tool
The CONNX DSN Registry tool enables JDBC connections to locate
and refer to the logical name of the data source. It must be installed on the
same machine as the CONNX JDBC server. See page - in this chapter for more
information on how to register a CONNX JDBC data source name.
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