How to use @vertx/sql-client - 4 common examples

app.get("/queries").handler(ctx => {
  let failed = false;
  let worlds = [];

  const queries = util.getQueries(ctx.request());

  for (let i = 0; i < queries; i++) {
    client.preparedQuery(SELECT_WORLD, Tuple.of(util.randomWorld()), ar => {
      if (!failed) {
        if (ar.failed()) {
          failed = true;
          ctx.fail(ar.cause());
          return;
        }

        // we need a final reference
        const row = ar.result().iterator().next();
        worlds.push({ id: row.getInteger(0), randomNumber: row.getInteger(1) });

        // stop condition
        if (worlds.length === queries) {
          ctx.response()
            .putHeader("Server", SERVER)
            .putHeader("Date", date)

.end(JSON.stringify({ message: 'Hello, World!' }));
});

const UPDATE_WORLD = "UPDATE world SET randomnumber=$1 WHERE id=$2";
const SELECT_WORLD = "SELECT id, randomnumber from WORLD where id=$1";
const SELECT_FORTUNE = "SELECT id, message from FORTUNE";

let connectOptions = new PgConnectOptions()
  .setCachePreparedStatements(true)
  .setHost('tfb-database')
  .setUser('benchmarkdbuser')
  .setPassword('benchmarkdbpass')
  .setDatabase('hello_world');

// Pool options
let poolOptions = new PoolOptions()
  .setMaxSize(1);

// Create the client pool
let client = PgPool.pool(vertx, connectOptions, poolOptions);

/*
 * This test exercises the framework's object-relational mapper (ORM), random number generator, database driver,
 * and database connection pool.
 */
app.get("/db").handler(ctx => {
  client.preparedQuery(SELECT_WORLD, Tuple.of(util.randomWorld()), res => {
    if (res.succeeded()) {
      let resultSet = res.result().iterator();

      if (!resultSet.hasNext()) {
        ctx.fail(404);

worlds.forEach(world => {
            batch.push(Tuple.of(world.randomNumber, world.id));
          });

app.route("/updates").handler(ctx => {
  let failed = false;
  let queryCount = 0;
  let worlds = [];

  const queries = util.getQueries(ctx.request());

  for (let i = 0; i < queries; i++) {
    const id = util.randomWorld();
    const index = i;

    client.preparedQuery(SELECT_WORLD, Tuple.of(id), ar => {
      if (!failed) {
        if (ar.failed()) {
          failed = true;
          ctx.fail(ar.cause());
          return;
        }

        const row = ar.result().iterator().next();

        worlds[index] = { id: row.getInteger(0), randomNumber: row.getInteger(1) };
        worlds[index].randomNumber = util.randomWorld();
        if (++queryCount === queries) {
          worlds.sort((a, b) => {
            return a.id - b.id;
          });