Connection string for PostgresSQL

In the example provided for dhtmlxConnector the connectionstring to PostgresSQL DB is missing. Can anyone share that?

public class postgre1 : dhtmlxRequestHandler
{
public override IdhtmlxConnector CreateConnector(HttpContext context)
{
dhtmlxGridConnector connector = new dhtmlxGridConnector(
“bookstore”,
“book_id, author”,
“book_id”,
dhtmlxDatabaseAdapterType.PostgreSQL,
ConfigurationManager.ConnectionStrings[“PostgreSQL”].ConnectionString

        );
        if (context.Request.QueryString["dynamic"] != null)
            connector.SetDynamicLoading(Convert.ToInt32(context.Request.QueryString["dynamic"]));
        return connector;
    }
}

Could you please, clarify what example are you meaning?