我用pdo创建了一个php数据库类来使用我的项目。它非常简单。但我注意到一件事，执行需要太多时间。你能告诉我我哪里做错了吗？
这是我的数据库类代码
class database{
public $error;
private $db;
private $dbhost = 'localhost';
private $dbname = 'support_database';
private $dbuser = 'root';
private $dbpass = '';
public $site_url = "http://localhost/support";
public function connect(){
try {
$this->db = new PDO("mysql:host={$this->dbhost};dbname={$this->dbname}",$this->dbuser,$this->dbpass);
$this->db->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
}
catch(PDOException $e) {
// echo "Connection error: ".$e->getMessage();
}
}
public function deleteRecord($id){
$this->Connect();
$statement = $this->db->prepare("delete from officers_table where id=?");
$statement->execute(array($id));
}
public function showRecord($tablename){
$this->Connect();
$statement = $this->db->prepare("select * from $tablename");
$statement->execute();
return $result = $statement->fetchAll(PDO::FETCH_ASSOC);
}
public function addRecord($tablename,$fields,$values){
$this->Connect();
$items = $fields;
$id = count($items);
$newarray = array();
for($i = 0; $i<$id; $i++){
$newarray[] = "?";
}
$nval = implode(",",$newarray);
$fields = implode(",",$fields);
$statement = $this->db->prepare("insert into $tablename ($fields) values($nval)");
$statement->execute($values);
return true;
}
public function addUser($tablename,$fields,$values){
$this->Connect();
$items = $fields;
$id = count($items);
$newarray = array();
for($i = 0; $i<$id; $i++){
$newarray[] = "?";
}
$nval = implode(",",$newarray);
$fields = implode(",",$fields);
$statement = $this->db->prepare("insert into $tablename ($fields) values($nval)");
$statement->execute($values);
return true;
}
public function checkUser($tablename,$field,$value){
$this->Connect();
$num = 0;
$statement = $this->db->prepare("select * from $tablename where $field=?");
$statement->execute(array($value));
$num = $statement->rowCount();
if($num>0)
{
return true;
}
else
{
return false;
}
}
public function SingleValueSearch($tablename,$field,$value,$id="id",$ordertype="DESC"){
$this->Connect();
$statement = $this->db->prepare("select * from $tablename where $field=? order by $id $ordertype");
$statement->execute(array($value));
return $result = $statement->fetchAll(PDO::FETCH_ASSOC);
}
public function allTicket($tablename){
$this->Connect();
$statement = $this->db->prepare("select * from $tablename order by id DESC");
$statement->execute();
return $result = $statement->fetchAll(PDO::FETCH_ASSOC);
}
public function userTicket($tablename,$field,$value,$id="id",$ordertype="DESC"){
$this->Connect();
$statement = $this->db->prepare("select * from $tablename where $field=? order by $id $ordertype");
$statement->execute(array($value));
return $result = $statement->fetchAll(PDO::FETCH_ASSOC);
}
public function currentUserId($email){
$this->Connect();
$statement = $this->db->prepare("select * from support_users where email=?");
$statement->execute(array($email));
return $result = $statement->fetchAll(PDO::FETCH_ASSOC);
}
public function lastId($tablename){
$this->Connect();
$statement = $this->db->prepare("select * from $tablename order by id DESC LIMIT 1");
$statement->execute();
return $result = $statement->fetchAll(PDO::FETCH_ASSOC);
}
public function emptyCheck($tablename,$user_id,$user_role){
$this->Connect();
$num = 0;
if($user_role == 'admin'){
$statement = $this->db->prepare("select * from $tablename");
$statement->execute();
$num = $statement->rowCount();
if($num>0){
return true;
}
else
{
return false;
}
}
else{
$statement = $this->db->prepare("select * from $tablename where user_id =?");
$statement->execute(array($user_id));
$num = $statement->rowCount();
if($num>0){
return true;
}
else
{
return false;
}
}
}
public function fileCheck($name) {
foreach ($_FILES[$name]['error'] as $ferror) {
if ($ferror != UPLOAD_ERR_NO_FILE) {
return true;
}
}
return false;
}
public function deleteTicket($id){
$this->Connect();
$statement = $this->db->prepare("select * from support_tickets where id=?");
$statement->execute(array($id));
$result = $statement->fetchAll(PDO::FETCH_ASSOC);
$media_id = unserialize($result[0]['media_id']);
foreach( $media_id as $mid ){
$statement = $this->db->prepare("delete from support_media where id=?");
$statement->execute(array($mid));
}
$statement = $this->db->prepare("delete from support_tickets where id=?");
$statement->execute(array($id));
return true;
}
}
在我的项目中，我使用的是这样的东西。以下链接的代码需要很长时间才能执行。我在此页面上仅使用了更多查询。
请帮助我找出我犯的错误。提前谢谢。
答案 0 :(得分：1)
您可以在现有代码中进行一些优化。
您目前正在为数据库的每个查询创建新连接。这很昂贵，所以你应该重用当前的连接。
在connect()方法的开头添加：
public function connect(){
if ($this->db) {
// There already is a connection, return it instead
return $this->db;
}
// Your current try/catch block
}
您还在同一个脚本中反复从数据库中提取相同的记录。即使DB调用很快（假设db已正确索引），它仍然是不必要的开销。您应该一次获取它，将其存储在变量中并重用变量：
$ticket = $db->SingleValueSearch('support_tickets','id',$_GET['id'],'id','DESC');
现在，您可以替换所有相同的调用，而不是使用变量$ticket。
答案 1 :(得分：-1)
根据Magnus Eriksson's说明我做了更改我的代码。现在它像火箭一样工作:)非常感谢Sir先生。
这是我的Connect方法的代码。我刚刚用if条件改变了。
public function connect(){
try {
if($this->db){
return $this->db;
}
else{
$this->db = new PDO("mysql:host={$this->dbhost};dbname={$this->dbname}",$this->dbuser,$this->dbpass);
$this->db->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
}
}
catch(PDOException $e) {
// echo "Connection error: ".$e->getMessage();
}
}