code: function getClient(callback) {
    if (!connectionOptions) {
      callback('Connection options missing. Please call db.connect before any other database functions to configure the database configuration');
    }
  
    if (activeBackend === 'mysql') {
      if (activeDb) {
        return callback(null, activeDb);
      }
      else {
        connect(connectionOptions);
        return callback(null, activeDb);
      }
    }
    else if (activeBackend === 'pgsql') {
      return pg.connect(connectionOptions, callback);
    }
  }
docs: Get the client object for the current database connection.