JDBC Package, Driver Class, and Environment Class

JDBC Package

Obtain the package from the release package GaussDB-Kernel_Database version number_OS version number_64bit_Jdbc.tar.gz.

After the decompression, you will obtain the following JDBC packages in .jar format:

• gsjdbc4.jar: The main class name is org.postgresql.Driver, and the URL prefix of the database connection is jdbc:postgresql. This driver package applies to the scenario where services are migrated from PostgreSQL. The driver class and loading path are the same as those before the migration, but the supported APIs are different. The APIs that are not supported need to be adjusted on the service side.
• gscejdbc.jar: The main class name is com.huawei.gaussdb.jdbc.Driver. The URL prefix of database connections is jdbc:gaussdb. This driver package contains the dependent libraries related to encryption and decryption that need to be loaded to the encrypted database. This driver package is recommended in encrypted scenarios. Currently, only EulerOS is supported. Before using the gscejdbc.jar driver package, set the environment variable LD_LIBRARY_PATH. For details, see "Setting Encrypted Equality Queries > Using JDBC to Operate an Encrypted Database" in Feature Guide.
• opengaussjdbc.jar: The main class name is com.huawei.opengauss.jdbc.Driver. The URL prefix of the database connection is jdbc:opengauss. This driver package is recommended. This driver package is used when both PostgreSQL and GaussDB are accessed in a JVM process.

• The loading paths and URL prefixes of driver classes vary in different driver packages, but the API functions are the same.
• gsjdbc200.jar: The main class name is com.huawei.gauss200.jdbc.Driver, and the URL prefix of the database connection is jdbc:gaussdb. This driver package applies to the scenario where services are migrated from GaussDB 200. The driver class and loading path are the same as those before the migration, but the supported APIs are different. The APIs that are not supported need to be adjusted on the service side.
• The gsjdbc4 driver package cannot be used to operate the PostgreSQL database. Although the connection can be successfully established in some versions, some API behaviors are different from those of PostgreSQL JDBC, which may cause unknown errors.
• The PostgreSQL driver package cannot be used to operate GaussDB. Although the connection can be successfully established in some versions, some API behaviors are different from those of GaussDB JDBC, which may cause unknown errors.

Driver Class

Before establishing a database connection, load the org.postgresql.Driver database driver class (corresponding to the gsjdbc4.jar file).

1. GaussDB is compatible with PostgreSQL in the use of JDBC. Therefore, when two JDBC drivers are used in the same process, class names may conflict.
2. JDBC of this version does not support identity & access management suite (IAM) for authentication.
3. Compared with the PostgreSQL driver, the GaussDB JDBC driver has the following enhanced features:
   1. The SHA256 encryption mode is supported for login.
   2. The third-party log framework that implements the sf4j API can be connected.
   3. Distributed load balancing at the connection level is supported.
   4. DR failover is supported.

Environment Class

The JDK1.8 must be configured on the client. JDK supports multiple platforms such as Windows and Linux. The following uses Windows as an example to describe how to configure JDK:

1. Enter java -version in the MS-DOS window (command prompt in Windows) to check the JDK version. Ensure that the JDK version is JDK1.8. If the JDK is not installed, download the installation package and install it.
2. On the Windows desktop, right-click This PC and choose Properties from the shortcut menu.
3. In the System window, click Advanced system settings in the navigation tree on the left.
4. In the System Properties dialog box, click Environment Variables in the lower right corner.
5. In the System variables area of the Environment Variables dialog box, set the following variables.

   Table 1 Variables

   Variable	Operation	Variable Value
   JAVA_HOME	If the variable exists, click Edit. If the variable does not exist, click New.	Specifies the Java installation directory. Example: C:\Program Files\Java\jdk1.8.0_131.
   Path	Click Edit.	If JAVA_HOME is configured, add %JAVA_HOME%\bin before the variable value. If JAVA_HOME is not configured, add the full Java installation path before the variable value: C:\Program Files\Java\jdk1.8.0_131\bin
   CLASSPATH	Click New.	%JAVA_HOME%\lib;%JAVA_HOME%\lib\tools.jar

6. Click OK and close the windows one by one.