Revised version of db_utils.php, refactored as a PHP class.

DatabaseUtils.php

<?php

/*
* DatabaseUtils.php - A class of simple database utilities.
* 
* Performs CRUD operations using PDO (MySQL) prepared statements.
*
* Author: bencentra (https://gist.github.com/bencentra/92228e1f4139436c4153)
*/

class DatabaseUtils 
{

  // Database connection object
  private $pdo;

  // Create a PDO object and connect to the database
  public function __construct($dbName, $dbHost, $dbUser, $dbPass) {
    try {
      // Instantiate the PDO object
      $this->pdo = new PDO(
        // Use MySQL database driver
        "mysql:dbname=$dbName;host=$dbHost", 
        $dbUser, 
        $dbPass, 
        // Set some options
        array(
          // Return rows found, not changed, during inserts/updates
          PDO::MYSQL_ATTR_FOUND_ROWS => true, 
          // Emulate prepares, in case the database doesn't support it
          PDO::ATTR_EMULATE_PREPARES => true,
          // Have errors get reported as exceptions, easier to catch
          PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION,
          // Return associative arrays, good for JSON encoding
          PDO::ATTR_DEFAULT_FETCH_MODE => PDO::FETCH_ASSOC
        )
      );
    } 
    catch (PDOException $e) {
        die('Database Connection Failed: ' . $e->getMessage());
    }
  }

  // Perform a SELECT query
  public function select($sql, $data = array()) {
    try {
      // Prepare the SQL statement
      $stmt = $this->pdo->prepare($sql);
      // Execute the statement
      if ($stmt->execute($data)) {
        // Return the selected data as an assoc array
        return $stmt->fetchAll(PDO::FETCH_ASSOC);
      }
      else {
        return false;
      }
    }
    catch (Exception $e) {
      return false;
    }
  }

  // Perform an INSERT query
  public function insert($sql, $data = array()) {
    try {
      // Prepare the SQL statement
      $stmt = $this->pdo->prepare($sql);
      // Execute the statement
      if ($stmt->execute($data)) {
        // Return the number of rows affected
        return $stmt->rowCount();
      }
      else {
        return false;
      }
    }
    catch (Exception $e) {
      return false;
    }
  }

  // Perform an UPDATE query
  public function update($sql, $data = array()) {
    return $this->insert($sql, $data);
  }

  // Perform a REPLACE query
  public function replace($sql, $data = array()) {
    return $this->replace($sql, $data);
  }

  // Perform a DELETE query
  public function delete($sql, $data = array()) {
    return $this->insert($sql, $data);
  }

  // Get the ID of the last row inserted
  public function lastInsertId() {
    return $this->pdo->lastInsertId();
  }

}

?>