[英]Database class, OOP - connect to mysql
This is database class: 这是数据库类:
DB.php db.php中
<?php
class DB {
public static $instance = null;
private $_pdo = null,
$_query = null,
$_error = false,
$_results = null,
$_count = 0;
private function __construct() {
try {
$this->_pdo = new PDO('mysql:host=' . Config::get('mysql/host') . ';dbname=' . Config::get('mysql/db'), Config::get('mysql/username'), Config::get('mysql/password'));
} catch(PDOExeption $e) {
die($e->getMessage());
}
}
public static function getInstance() {
// Already an instance of this? Return, if not, create.
if(!isset(self::$instance)) {
self::$instance = new DB();
}
return self::$instance;
}
public function query($sql, $params = array()) {
$this->_error = false;
if($this->_query = $this->_pdo->prepare($sql)) {
$x = 1;
if(count($params)) {
foreach($params as $param) {
$this->_query->bindValue($x, $param);
$x++;
}
}
if($this->_query->execute()) {
$this->_results = $this->_query->fetchAll(PDO::FETCH_OBJ);
$this->_count = $this->_query->rowCount();
} else {
$this->_error = true;
}
}
return $this;
}
public function get($table, $where) {
return $this->action('SELECT *', $table, $where);
}
public function delete($table, $where) {
return $this->action('DELETE', $table, $where);
}
public function action($action, $table, $where = array()) {
if(count($where) === 3) {
$operators = array('=', '>', '<', '>=', '<=');
$field = $where[0];
$operator = $where[1];
$value = $where[2];
if(in_array($operator, $operators)) {
$sql = "{$action} FROM {$table} WHERE {$field} {$operator} ?";
if(!$this->query($sql, array($value))->error()) {
return $this;
}
}
return false;
}
}
public function insert($table, $fields = array()) {
$keys = array_keys($fields);
$values = null;
$x = 1;
foreach($fields as $value) {
$values .= "?";
if($x < count($fields)) {
$values .= ', ';
}
$x++;
}
$sql = "INSERT INTO {$table} (`" . implode('`, `', $keys) . "`) VALUES ({$values})";
if(!$this->query($sql, $fields)->error()) {
return true;
}
return false;
}
public function update($table, $id, $fields = array()) {
$set = null;
$x = 1;
foreach($fields as $name => $value) {
$set .= "{$name} = ?";
if($x < count($fields)) {
$set .= ', ';
}
$x++;
}
$sql = "UPDATE users SET {$set} WHERE id = {$id}";
if(!$this->query($sql, $fields)->error()) {
return true;
}
return false;
}
public function results() {
// Return result object
return $this->_results;
}
public function first() {
return $this->_results[0];
}
public function count() {
// Return count
return $this->_count;
}
public function error() {
return $this->_error;
}
}
I was looking this database approach and it seems very practical and useful. 我一直在寻找这种数据库方法,它似乎非常实用和有用。 I'm beginner at oop and still learning.
我是oop的新手,还在学习。 The requestQuote would look something like this:
requestQuote看起来像这样:
How do I bindParam in query like this? 我如何在这样的查询中绑定param?
requestQuote = DB::getInstance()->query("");
(form DB.class) (形成DB.class)
This is code I have right now: 这是我现在拥有的代码:
$request = "";
if ($_POST) {
$request = $_POST["request"];
} else if (isset($_GET["request"])) {
$request = $_GET["request"];
}
$requestQuote="%" . $request . "%";
$sql = $conn -> prepare("SELECT * FROM users WHERE concat(name, ' ',lastname, ' ', user_id) LIKE :request limit " . (($page * 50)-50) . ",50");
$sql->bindParam(":request", $requestQuote);
$sql -> execute();
$results = $sql -> fetchAll(PDO::FETCH_OBJ);
When I put it like this, then pagination works. 当我这样说时,分页就起作用了。 But I need search form... and that won't work...
但是我需要搜索表格...这是行不通的...
$sql= DB::getInstance()->query(
"SELECT * FROM users
WHERE (category='admin')
LIMIT " . (($page* 5)-5) . ",5");
@Paul was close but you got one more issue: @Paul离得很近,但您又遇到了一个问题:
Check this part of the class: 检查课程的这一部分:
$x = 1;
if(count($params)) {
foreach($params as $param) {
$this->_query->bindValue($x, $param);
$x++;
}
}
It is not binding with named place holder, you need to change the code: 它不与命名的占位符绑定,您需要更改代码:
$limit = ($page * 50)-50;
$params = array('%lolcats%', $limit);
$query =
"SELECT * FROM users
WHERE concat(name, ' ',lastname, ' ', user_id)
LIKE ?
LIMIT ?,50";
$results = DB::getInstance()->query($query, $params);
or change the class code to bind by placeholder, something along the following lines: 或更改类代码以使用占位符进行绑定,具体方法如下:
#$params = array(':request' =>'%lolcats%', ':limit'=>$limit);
if(count($params)) {
foreach($params as $key=>$value) {
$this->_query->bindValue($key, $value);
}
}
Looking at this class, the second argument of query
function is an optional array of parameters so use this to pass the parameters for your request: 查看此类,
query
函数的第二个参数是参数的可选数组,因此可使用此参数为您的请求传递参数:
$params = array(':request' => 'lolcats');
$limit = $page - 1 * 50;
$query = sprintf(
"SELECT * FROM users
WHERE concat(name, ' ',lastname, ' ', user_id)
LIKE :request
LIMIT %d,50",
$limt
);
$results = DB::getInstance()->query($query, $params);
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