/**
*
* Database.
*
* Version 1.2 (March 2017).
*
**/

class Database {

    // Connection information.
    private $connection;

    // SQL querey information.
    private $querey;

    // Connected to the database server.
    private $connected = false;

    // Errors.
    private $error;

    // Hostname or IP address of the database server.
    private $host = "127.0.0.1";

    // Port to access the database server.
    private $port = 3306;

    // Name of the database.
    private $database = "test";

    // Username.
    private $username = "test";

    // Password.
    private $password = "qgmxnMVroz9PHTY36Eq4qwpA5GSXwFyb";

    // Database charset.
    private $charset = "UTF8";

    // PDO options.
    private $options = [
        PDO::ATTR_DEFAULT_FETCH_MODE => PDO::FETCH_ASSOC,
        PDO::ATTR_EMULATE_PREPARES => false,
        PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION,
        PDO::ATTR_PERSISTENT => true
    ];

    /**
    *
    * Constructor.
    *
    * Creates connection to the database server.
    *
    **/

    public function __construct() {

        if ($this->connected === true) {

            return true;

        } else {

            try {

                $this->connection = new PDO("mysql:host={$this->host};port={$this->port};dbname={$this->database};charset={$this->charset}", $this->username, $this->password, $this->options);

                $this->connected = true;

            } catch (PDOException $e) {

                $this->error = $e->getMessage();

                return null;

            }

        }

    }

    /**
    *
    * Query the Database.
    *
    * Used for SELECT, INSERT, UPDATE and DELETE statements.
    *
    **/

    public function query($query, $parameters = [], $expectSingleResult = false) {

        if ($this->connected === true) {

            if (is_string($query) && $query !== "" && is_array($parameters) && is_bool($expectSingleResult)) {

                try {

                    // Prepare SQL querey.
                    $this->querey = $this->connection->prepare($query);

                    // Bind parameters to SQL querey.
                    foreach ($parameters as $placeholder => $value) {

                        // Parameter type.
                        if (is_string($value)) {

                            // Parameter is a string.
                            $type = PDO::PARAM_STR;

                        } elseif (is_int($value)) {

                            // Parameter is a integer.
                            $type = PDO::PARAM_INT;

                        } elseif (is_bool($value)) {

                            // Parameter is a boolean.
                            $type = PDO::PARAM_BOOL;

                        } else {

                            // Parameter is NULL.
                            $type = PDO::PARAM_NULL;

                        }

                        // Bind parameter.
                        $this->querey->bindValue($placeholder, $value, $type);

                    }

                    // Execute SQL querey.
                    $this->querey->execute();

                    // Get Result of SQL querey.
                    if ($expectSingleResult === true) {

                        $results = $this->querey->fetch();

                    } else {

                        $results = $this->querey->fetchAll();

                    }

                    // Return results of SQL querey.
                    return $results;

                } catch (PDOException $e) {

                    $this->error = $e->getMessage();

                }

            } else {

                $this->error = "Invalid Querey or Paramaters";

                return null;

            }

        } else {

            $this->error = "Not Connected to Database Server";

            return null;

        }

    }

    /**
    *
    * Row count for the last querey.
    *
    **/

    public function rowCount() {

        if ($this->connected === true) {

            return $this->querey->rowCount();

        } else {

            $this->error = "Not Connected to Database Server";

            return null;

        }

    }

    /**
    *
    * Get ID for the last querey.
    *
    **/

    public function lastId() {

        if ($this->connected === true) {

            return $this->connection->lastInsertId();

        } else {

            $this->error = "Not Connected to Database Server";

            return null;

        }

    }

    /**
    *
    * Begin a transaction.
    *
    **/

    public function beginTransaction() {

        if ($this->connected === true) {

            return $this->connection->beginTransaction();

        } else {

            $this->error = "Not Connected to Database Server";

            return null;

        }

    }

    /**
    *
    * Rollback and cancel/end a transaction.
    *
    **/

    public function cancelTransaction() {

        if ($this->connected === true) {

            return $this->connection->rollBack();

        } else {

            $this->error = "Not Connected to Database Server";

            return null;

        }

    }

    /**
    *
    * Or...
    *
    **/

    public function rollbackTransaction() {

        if ($this->connected === true) {

            return $this->connection->rollBack();

        } else {

            $this->error = "Not Connected to Database Server";

            return null;

        }

    }

    /**
    *
    * Commit and end a transaction.
    *
    **/

    public function endTransaction() {

        if ($this->connected === true) {

            return $this->connection->commit();

        } else {

            $this->error = "Not Connected to Database Server";

            return null;

        }

    }

    /**
    *
    * Close the current connection the the database server.
    *
    **/

    public function close() {

        $this->connection = null;

    }

}

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