Driver resources

The driver resources are parameters you can set to modify the behavior of the LN Oracle database driver; you set these parameters in a file called the resource file (db_resource). One resource file is available for all database drivers that run in an LN environment, where you can also find resources for all the database driver types. When you first invoke the driver, a database driver reads the parameters set in the resource file.

The resource file can contain many entries, with one entry for each line. Each entry is used to set a single resource parameter, with the resource name followed by a colon and then the value to which the resource is to be set. This is an example of the contents of a resource file that contains two entries:

oracle_home:/usr/oracle/product/11gR2

ora_timeout:{300,300,300,300,300}

If you modify the behavior of the database driver, to take advantage of the characteristics of the database driver, you often must modify the behavior of the LN application virtual machine; therefore, two types of database driver resources are available: those you use to modify the behavior of the database driver, and those you use to modify the behavior of the application virtual machine. Driver resources you use to modify database driver behavior are called resources for the server. Driver resources you use to modify behavior in the application virtual machine are called resources for the client.

In a Windows environment, the resource file db_resource is located in the directory %BSE%\lib\defaults, where %BSE% refers to the directory on which the LN software environment is installed. In a UNIX environment, the resource file is located in the directory $BSE/lib/defaults, where $BSE refers to the directory on which the LN software environment is installed. If the database driver and the application virtual machine run on the same machine, only one db_resource file is created, which contains all the required resource parameters. If the database driver and the application virtual machine run on separate machines, one db_resource file must be located on the machine that runs the database driver that contains the server resources. And one db_resource file must be located on the machine that runs the application virtual machine that contains the client resources.

Besides the default resource file db_resource, to override resource values for specific users or groups of users, you can setup an alternative resource file. Specify the alternative resource file with the environment variables USR_DBS_RES and USR_DBC_RES. USR_DBS_RES specifies the path to a file that contains an alternative resource file for the server. You must set this file on the machine that runs the database driver. Use USR_DBC_RES to specify the path to a file that contains an alternative resource file for the client. You can set this file on the machine that runs the application virtual machine. Any driver resource set in the alternative resource file overrides the setting of the same driver resource in db_resource.

For more information about setting the database driver environment variables, see Environment variables.