1 Introducing JDBC

Common Features of Oracle JDBC Drivers

The server-side and client-side Oracle JDBC drivers provide the same basic functionality.

The JDBC Thin and OCI drivers support Java Development Kit (JDK) 1.5 and 1.6. The server-side internal drivers support only JDK 1.5. All the JDBC drivers support the following standards and features:

• Same syntax and APIs

• Same Oracle extensions

• Full support for multithreaded applications

Oracle JDBC drivers implement the standard java.sql interfaces. You can access the Oracle-specific features, in addition to the standard features, by using the oracle.jdbc package.

JDBC Thin Driver

The JDBC Thin driver is a pure Java, Type IV driver that can be used in applications and applets. It is platform-independent and does not require any additional Oracle software on the client-side. The JDBC Thin driver communicates with the server using SQL*Net to access Oracle Database.

The JDBC Thin driver allows a direct connection to the database by providing an implementation of SQL*Net on top of Java sockets. The driver supports the TCP/IP protocol and requires a TNS listener on the TCP/IP sockets on the database server.

JDBC OCI Driver

The JDBC OCI driver is a Type II driver used with Java applications. It requires an Oracle client installation and, therefore, is Oracle platform-specific. It supports all installed Oracle Net adapters, including interprocess communication (IPC), named pipes, TCP/IP, and Internetwork Packet Exchange/Sequenced Packet Exchange (IPX/SPX).

The JDBC OCI driver, written in a combination of Java and C, converts JDBC invocations to calls to OCI, using native methods to call C-entry points. These calls communicate with the database using SQL*Net.

The JDBC OCI driver uses the OCI libraries, C-entry points, Oracle Net, core libraries, and other necessary files on the client computer where it is installed.

OCI is an API that enables you to create applications that use the native procedures or function calls of a third-generation language to access Oracle Database and control all phases of the SQL statement processing.

JDBC Server-Side Thin Driver

The JDBC server-side Thin driver offers the same functionality as the JDBC Thin driver that runs on the client-side. However, the JDBC server-side Thin driver runs inside Oracle Database and accesses a remote database or a different session on the same database.

This driver is useful in the following scenarios:

• Accessing a remote database server from an Oracle Database instance acting as a middle tier

• Accessing an Oracle Database session from inside another, such as from a Java stored procedure

The use of JDBC Thin driver from a client application or from inside a server does not affect the code.

JDBC Server-Side Internal Driver

The JDBC server-side internal driver supports any Java code that runs inside Oracle Database, such as in a Java stored procedure, and must access the same database. It lets the Oracle Java Virtual Machine (Oracle JVM) to communicate directly with the SQL engine. This driver supports only JDK 1.5.

The JDBC server-side internal driver, the Oracle JVM, the database, and the SQL engine all run within the same address space, and therefore, the issue of network round-trips is irrelevant. The programs access the SQL engine by using function calls.

The JDBC server-side internal driver is fully consistent with the client-side drivers and supports the same features and extensions.

Choosing the Appropriate Driver

Consider the following when choosing a JDBC driver for your application or applet:

• In general, unless you need OCI-specific features, such as support for non-TCP/IP networks, use the JDBC Thin driver.

• If you want maximum portability and performance, then use the JDBC Thin driver. You can connect to Oracle Database from either an application or an applet using the JDBC Thin driver.

• If you want to use Lightweight Directory Access Protocol (LDAP) over Secure Sockets Layer (SSL), then use the JDBC Thin driver.

• If you are writing a client application for an Oracle client environment and need OCI-driver-specific features, such as support for non-TCP/IP networks, then use the JDBC OCI driver.

• If you are writing an applet, then you must use the JDBC Thin driver.

• For code that runs in the database server and needs to access a remote database or another session within the same database instance, use the JDBC server-side Thin driver.

• If your code runs inside the database server and needs to access data locally within the session, then use the JDBC server-side internal driver to access that server.

Feature Differences Between JDBC OCI and Thin Drivers

Table 1-1 lists the features that are specific either to the JDBC OCI or JDBC Thin driver in Oracle Database 11g Release 2 (11.2).

Supported JDK and JDBC Versions

In Oracle Database 11g Release 2 (11.2), all the JDBC drivers are compatible with JDK 1.5. The JDBC Thin and OCI drivers also support JDK 1.6. All versions of JDK earlier than 1.5 are no longer supported. Support for JDK 1.5 and 1.6 is provided through the ojdbc5.jar and ojdbc6.jar files, respectively.

JNI and Java Environments

The JDBC OCI driver uses the standard Java Native Interface (JNI) to call OCI C libraries. You can use the JDBC OCI driver with Java Virtual Machines (JVMs) other than that of Sun Microsystems, in particular, with Microsoft and IBM JVMs.

JDBC and IDEs

The Oracle JDeveloper Suite provides developers with a single, integrated set of products to build, debug, and deploy component-based database applications for the Internet. The Oracle JDeveloper environment contains integrated support for JDBC, including the JDBC Thin driver and the native OCI driver. The database component of Oracle JDeveloper uses the JDBC drivers to manage the connection between the application running on the client and the server.