I'm new to php oop.here i wanted to do database connectivity with singleton class but i got error like this: Fatal error: Call to a member function getOne() on a non-object in C:\xampp\htdocs\singleton\new\singleton_db.php here i have given two file
1.singleton_db.php
<?php
class database
{
public $query;
public $results;
public $conn;
public static $database;
//connect to the database
public function __construct()
{
$this->conn = mysql_connect('localhost','root','');
if ($this->conn)
{
mysql_select_db('test1');
}
}
public static function instance()
{
if (!isset(self::$database)) {
self::$database = new database();
}
return self::$database;
}
function getOne($sql) {
$result = $this->conn->getOne($sql); //Error in this line
if(database::isError($result)) {
throw new Exception($result->getMessage(), $result->getCode());
}
return $result;
}
function startTransaction() {
//autoCommit returns true/false if the command succeeds
return $this->conn->autoCommit(false);
}
function commit() {
$result = $this->conn->commit();
if(database::isError($result)) {
throw new Exception($result->getMessage(), $result->getCode());
}
$this->conn->autoCommit(true);
return true;
}
function abort() {
$result = $this->conn->rollback();
if(database::isError($result)) {
throw new Exception($result->getMessage(), $result->getCode());
}
return true;
}
//returns numerically indexed 1D array of values from the first column
public function insert($table, $arFieldValues) {
$fields = array_keys($arFieldValues);
$values = array_values($arFieldValues);
// Create a useful array of values
// that will be imploded to be the
// VALUES clause of the insert statement.
// Run the mysql_real_escape_string function on those
// values that are something other than numeric.
$escVals = array();
foreach($values as $val) {
if(! is_numeric($val)) {
//make sure the values are properly escaped
$val = "'" . mysql_real_escape_string($val) . "'";
}
$escVals[] = $val;
}
//generate the SQL statement
$sql = " INSERT INTO $table (";
$sql .= join(', ', $fields);
$sql .= ') VALUES(';
$sql .= join(', ', $escVals);
$sql .= ')';
$hRes = mysql_query($sql);
if(! is_resource($hRes)) {
$err = mysql_error($this->conn) . "\n" . $sql;
throw new Exception($err);
}
return mysql_affected_rows($hRes);
}
}
2.data.php
<?php
require_once('singleton_db.php');
try {
$db = database::instance();
} catch (Exception $e) {
// No point continuing...
die("Unable to connect to the database.");
}
$sql = "SELECT count(1) FROM mytable";
$count = $db->getOne($sql);
print "There are $count records in mytable!<br>\n";
// start a transaction
$db->startTransaction();
// do an insert and an update
try {
$arValues = array();
$arValues['id'] = '#id#';
$arValues['myval'] = 'blah blah blah';
$newID = $db->insert('mytable', $arValues);
print "The new record has the ID $newID<br>\n";
// update the record we just created
$arUpdate = array();
$arUpdate['myval'] = 'foobar baz!';
$affected = $db->update('mytable', $arUpdate, "id = $newID");
print "Updated $affected records<br>\n";
// write the changes to the database
$db->commit();
} catch (Exception $e) {
// some sort of error happened - abort the transaction
// and print the error message
$db->abort();
print "An error occurred.<br>\n" . $e->getMessage();
}
?>
What could I do to fix this ?
