Warning: mysqli_query() expects at least 2 parameters, 1 given in dbcontroller.php on line 49

Warning: mysqli_error() expects exactly 1 parameter, 0 given in dbcontroller.php on line 51
Invalid query:


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<?php
class DBController {
	private $host = "localhost";
	private $user = "";
	private $password = "";
	private $database = "";

	function __construct() {
		$conn = $this->connectDB();
		if(!empty($conn)) {
			$this->selectDB($conn);
		}
	}a

	function connectDB() {
		$conn = mysqli_connect($this->host,$this->user,$this->password);
		return $conn;
	}

	function selectDB($conn) {
		mysqli_select_db($conn, $this->database);
	}

	function runQuery($query) {
		$result = mysqli_query($query);
		while($row=mysqli_fetch_assoc($result)) {
			$resultset[] = $row;
		}
		if(!empty($resultset))
			return $resultset;
	}

	function numRows($query) {
		$result  = mysqli_query($query);
		$rowcount = mysqli_num_rows($result);
		return $rowcount;
	}

	function updateQuery($query) {
		$result = mysqli_query($query);
		if (!$result) {
			die('Invalid query: ' . mysqli_error());
		} else {
			return $result;
		}
	}

	function insertQuery($query) {
		$result = mysqli_query($query);
		if (!$result) {
			die('Invalid query: ' . mysqli_error());
		} else {
			return $result;
		}
	}

	function deleteQuery($query) {
		$result = mysqli_query($query);
		if (!$result) {
			die('Invalid query: ' . mysqli_error());
		} else {
			return $result;
		}
	}
}
?>