Postgresql in Dart v2

I got from my previous post, a lot of great feedback. so I have updated the code from that.

I use the same database, but as +Niklas Collin rightful said: "... those queries are vulnerable to SQL injection and are thus useless in any real code. Would have rather liked to see a prepared statement example...". So I have made a Prepared Statement and a Stored Procedure function to insert the data with.

	CREATE OR REPLACE FUNCTION
	InsertPerson(text, text, timestamp, double precision)
	RETURNS
	INTEGER
	AS
	$delimiter$
	INSERT INTO person(firstname, lastname, dateofbirth, height) VALUES
	($1, $2, $3, $4)
	RETURNING id
	$delimiter$
	LANGUAGE SQL;

view raw gistfile1.sql hosted with ❤ by GitHub

	import 'dart:async';
	import 'package:postgresql/postgresql.dart';
	void main() {
	var username = "TheRightMan";
	var password = "WithTheRightSecret";
	var DBname = "AtTheRightPlace";
	var uri = 'postgres://$username:$password@localhost:5432/$DBname';
	connect(uri)
	.then((Connection connection) =>
	insertPersonStored(connection, "Thomas", "Pedersen", new DateTime(1988, 9, 23), 1.80))
	.then((Connection connection) =>
	insertPersonPrepared(connection, "Donald", "Duck", new DateTime(1934, 2, 13), 1.31))
	.then((connection) =>
	printEntireTable(connection))
	.then((connection) =>
	connection.close())
	.catchError((e) =>
	print("Error: $e"));
	}
	Future insertPersonStored(Connection connection, String firstname, String lastname, DateTime dateOfBirth, double height) {
	final String query = "SELECT insertperson('$firstname', '$lastname', '$dateOfBirth', $height);";
	return connection.query(query).listen((row) {
	print("Inserted: (${row[0]}) $firstname $lastname, $dateOfBirth, $height");
	}).asFuture(connection);
	}
	Future insertPersonPrepared(Connection connection, String firstname, String lastname, DateTime dateOfBirth, double height) {
	final String query =
	'insert into person(firstname, lastname, dateOfBirth, height)'+
	' values (@firstname, @lastname, @dateOfBirth, @height);';
	return connection.execute(query,
	{'firstname' : firstname,
	'lastname' : lastname,
	'dateOfBirth': dateOfBirth,
	'height' : height})
	.then((rowsAffected) {
	print("rowsAffected: $rowsAffected");
	return connection;
	}
	);
	}
	Future printEntireTable(Connection connection) {
	final String query = "SELECT id, firstname, lastname, dateofbirth, height FROM person;";
	return connection.query(query).listen((row) {
	var age = ((new DateTime.now()).difference(row.dateofbirth).inDays/365.2425).floor();
	print("(${row.id}) ${row.firstname} ${row.lastname} - $age years old - ${row.height}m");
	}).asFuture(connection);
	}

view raw gistfile1.dart hosted with ❤ by GitHub

Now the code look a lot prettier thanks to the comment from +Justin Fagnani and +Seth Ladd about futures, and as far as I know, it shouldn't be vulnerable to SQL injection any more.