Prepare the runtime environment - connecting to the database

In order to connect to PostgreSQL, you must have a PostgreSQL database driver "dbmpgs" in FGLDIR/dbdrivers. On HP/UX LP64, the PostgreSQL database driver must be linked with the libxnet library if you want to use networking.

The PostgreSQL client software is required to connect to a database server. Check whether the PostgreSQL client library (libpq.*) is installed on the machine where the BDL programs run.

Make sure that the PostgreSQL client environment variables are properly set. Check, for example, PGDIR (the path to the installation directory), PGDATA (the path to the data files directory), etc. See the PostgreSQL documentation for more details.

Check the database client locale settings (for example, set the PGCLIENTENCODING environment variable). The database client locale must match the locale used by the runtime system (LC_ALL, LANG).

Verify the environment variable defining the search path for the PostgreSQL database client shared libraries (libpq.so on UNIX™, LIBPQ.DLL on Windows™).

Table 1. Shared library environment setting for PostgreSQL
PostgreSQL version	Shared library environment setting
PostgreSQL 9.0 and higher	UNIX: Add $PGDIR/lib to LD_LIBRARY_PATH (or its equivalent). Windows: Add %PGDIR%\bin to PATH.

To verify if the PostgreSQL client environment is correct, you can start the PostgreSQL command interpreter:

$ psql dbname -U appadmin -W

Set up the fglprofile entries for database connections.

Define the PostgreSQL database driver:
```
dbi.database.dbname.driver = "dbmpgs"
```
The 'source' parameter defines the name of the PostgreSQL database, as well as additional connection parameters if needed, such as the server host name, the TCP port and specific PostgresSQL connection options.
```
dbi.database.dbname.source = "test1"
```
The source parameter must have the following form:
```
dbname[@host[:port]][?options]
```
where:
- dbname defines the name of the PostgreSQL database
- host defines the server host name, or IP address (IPv6 host address needs to be enclosed it in square brackets)
- port defines the TCP port
- options is a URI-style query string defining PostgreSQL connection parameters
For example:
```
mydb@orion:5433?connect_timeout=10&application_name=myapp
```