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

JDBC Driver Types

The following table describes the types of JDBC drivers.

JDBC Driver Types

Type

Written in Java Description

No. Name

1 JDBC-to-ODBC bridge Possibly Uses a JDBC-to-ODBC bridge to translate JDBC calls into ODBC calls,

which are handled by an ODBC driver. This requires an ODBC driver on

the client side and an ODBC server on the server side.

2 Native protocol Partially Translates JDBC calls into the native API for a particular database. The

driver must run on a machine where this native API is available. (sqlmp

and sqlmptx are Type 2 drivers.)

3 Pure Java Entirely Translates JDBC calls into a database-independent protocol for

transmission over the network. Server middleware then translates this

protocol into a database's native protocol.

4 Native protocol,

Pure Java

Entirely Translates JDBC calls directly into the network protocol of a particular

database. Thus, a JDBC program on the client can call directly to the

database server.

Note: Compaq does not support third-party JDBC drivers, but any JDBC driver that is written entirely in

Java (that is, a Type 3 or a Type 4 driver) can run on top of NSJ. To use such a driver to connect your Java

program to a third-party database, see the third-party instructions for that driver.

This subsection explains these subjects:

Original SQL/MP Driver●

Transaction-Aware SQL/MP Driver●

Original SQL/MP Driver

The original SQL/MP driver, sqlmp, manages transactions itself. You do not need to explicitly begin and end

transactions using Current class methods.

Note: If you call the original driver after beginning a transaction using Current.begin() (that is, if you

create an active transaction in the thread), the driver throws an SQLMPException.

By default, the original driver connects to an SQL/MP database using autocommit mode, but it can also use

nonautocommit mode.

The following table shows how the original driver behaves when the JDBC method

Connection.createStatement() or Connection.prepareStatement() is called, depending on the

connection mode and whether an active transaction exists in the thread.

Effect of Mode and Transaction Status on Original Driver

Transaction Status

Active transaction in thread No active transaction in thread

Autocommit

(default)

Throws an SQLMPException.

Creates a new transaction for each statement.

Nonautocommit

Throws an SQLMPException.

Creates a new transaction for this connection.