For SQL queries that affects data in MySQL database, it is indicated to use placeholder names (or question marks) in the SQL statement, and pass the associated values separately into an array. Data will be added Safely in MySQL database.
<?php
// Array with data for connecting to mysql database
$mysql = array(
'host'=> 'localhost',
'user'=> 'root',
'pass'=> 'password',
'bdname'=> 'db_name'
);
include('class.pdo_mysqli.php'); // includes the php file with pdo_mysqli class
// creates object with connection to MySQL
$conn = new pdo_mysqli($mysql);
3. Define the SQL query (optional, array with values for placeholders in SQL), and call the sqlExec() method, passing the SQL query string, and optional the array with values. You can use named or question mark placeholders in the SQL statement (see the examples from downloaded archive).
// Select with named placeholder
$sql = "SELECT * FROM table_name WHERE column = :val";
$values = array('val'=>'value');
$rows = $conn->sqlExec($sql, $values);
// OR, Select without placeholders
$sql = "SELECT * FROM table_name WHERE id = 8";
$rows = $conn->sqlExec($sql);
// traverses the array with rows data
foreach($rows AS $row) {
echo $row['column'];
}
// Select to get the columns data
$sql = "SELECT * FROM table_name WHERE column = :val";
$val = array('id'=>2);
$conn->fetch = 'assoc'; //to return data associated to column-name only
$conn->group = 'cols'; //to group the result set by columns
$cols = $conn->sqlExec($sql, $val);
// check if the SQL query succesfully performed
if($cols) {
// traverses values added in the 'col_name' column
foreach($cols['col_name'] AS $val) {
echo '<br>'. $val;
}
}
else if($conn->error) echo $conn->error;
//reset $group to default value, if I want the next Select to return data grouped by rows
$conn->group = '';
<?php
define('CONN_MOD', 'mysqli'); //sets default connection method: 'pdo', or 'mysqli'
// class to connect to MySQL, and perform easily and safe SQL queries
// From - https://coursesweb.net/php-mysql/
class pdo_mysqli {
protected $conn_mod =''; // 'pdo', or 'mysqli'
protected $conn = false; // stores the connection to mysql
protected $conn_data = []; // to store data for connecting to database
public $mysql_version =''; // mysql server version
public $fetch =''; // 'assoc' - columns with named index, 'num' - columns numerically indexed, Else - both
public $group =''; //If 'cols': returns data grouped by columns; Otherwise, return Select results grouped by Rows.
public $affected_rows =0; // number affected rows for Insert, Update, Delete
public $num_rows =0; // number of rows from Select /Show results
public $num_cols =0; // number of columns from Select /Show results
public $last_insertid; // stores the last ID in an AUTO_INCREMENT column, after Insert query
public $nr_queries =0; // to store number of sql queries
public $error = false; // to store and check for errors
function __construct($conn_data){
$this->conn_data = $conn_data; //stores connection data to MySQL database
}
// to set the connection to mysql, with PDO, or MySQLi
protected function setConn($conn_data) {
// sets the connection method, check if can use pdo or mysqli (with MySQLnd)
if(CONN_MOD == 'mysqli') {
if(extension_loaded('mysqli') === true && function_exists('mysqli_get_client_stats')) $this->conn_mod ='mysqli';
else if(extension_loaded('PDO') === true) $this->conn_mod ='pdo';
}
else if(CONN_MOD == 'pdo') {
if(extension_loaded('PDO') === true) $this->conn_mod ='pdo';
else if(extension_loaded('mysqli') === true && function_exists('mysqli_get_client_stats')) $this->conn_mod ='mysqli';
}
if($this->conn_mod == 'mysqli') $this->connMySQLi($conn_data);
else if($this->conn_mod == 'pdo') $this->connPDO($conn_data);
else $this->setSqlError('Unable to use PDO or MySQLi');
//if error, output it
if($this->error !== false) echo 'Error: '. $this->error;
}
// for connecting to mysql with PDO
protected function connPDO($conn_data) {
try {
// Connect and create the PDO object
$this->conn = new PDO("mysql:host=".$conn_data['host']."; dbname=".$conn_data['bdname'], $conn_data['user'], $conn_data['pass']);
// Sets to handle the errors in the ERRMODE_EXCEPTION mode
$this->conn->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
$this->mysql_version = str_replace('.', '', $this->conn->getAttribute(PDO::ATTR_SERVER_VERSION));
// Sets transfer with encoding UTF-8
$this->conn->exec('SET character_set_client="utf8",character_set_connection="utf8",character_set_results="utf8";');
}
catch(PDOException $e) {
$this->setSqlError($e->getMessage());
}
}
// method that create the connection to mysql with MySQLi
protected function connMySQLi($conn_data) {
// if the connection is successfully established
$this->conn = new mysqli($conn_data['host'], $conn_data['user'], $conn_data['pass'], $conn_data['bdname']);
if(mysqli_connect_errno()){
$this->setSqlError('MySQL connection failed: '. mysqli_connect_error());
$this->conn = false;
}
else {
$this->mysql_version = strval($this->conn->server_version);
$this->conn->query('SET character_set_client="utf8",character_set_connection="utf8",character_set_results="utf8";');
}
}
// Performs SQL queries
// $sql - SQL query with prepared statement
// $param - array of values for SQL query
public function sqlExec($sql, $param=[]) {
if($this->conn === false || $this->conn === NULL) $this->setConn($this->conn_data); // sets the connection to mysql
// resets previous regstered data
$this->affected_rows = 0;
$this->num_rows = 0;
$this->num_cols = 0;
// if there is a connection set ($conn property not false)
if($this->conn !== false){
// gets the first word in $sql, to determine when SELECT query
$mode = explode(' ', trim(preg_replace('/[^A-z ]+/i', '', str_ireplace(PHP_EOL, ' ', $sql))), 2);
$mode = strtolower($mode[0]);
$this->error = false; // to can perform current $sql if previous has error
$nr_p = count($param); // number of elements for placeholders
// code to replace ":placeholder" with "?" (for MySQLi)
if($this->conn_mod == 'mysqli') {
// check if number of :placeholders match number of items in $param. If they match, replace :placeholder with ? (for MySQLi)
// else, replace :placeholder with its value, and empty $param
if(preg_match_all('/:[^,|"|\'|;|\)\} ]*/i', $sql, $mt)){
$nr_m = count($mt[0]);
if($nr_p == $nr_m) $sql = preg_replace('/:[^,|"|\'|;|\)\} ]*/i','?', $sql);
else {
foreach($param AS $k => $v) {
if(is_string($v)) $v = "'". str_replace("'", "\\'", $v) ."'";
$sql = str_ireplace(':'. $k, $v, $sql);
}
$param = []; $nr_p = 0;
}
}
}
$sqlre = $this->conn->prepare($sql); // prepares statement
// if successfully prepared execute query
if(is_object($sqlre)){
if($this->conn_mod == 'mysqli'){
// if values in $param, sets to use "bind_param" before execute()
if($nr_p >0){
// stores in $args[0] the type of the value of each value in $param, the rest of items in $args are the values
$args = [''];
foreach($param AS $k=>$v) {
if(is_int($v)) $args[0] .= 'i';
else if(is_double($v)) $args[0] .= 'd';
else $args[0] .= 's';
$args[] = &$param[$k];
}
// binds the values with their types in prepared statement
call_user_func_array([$sqlre,'bind_param'], $args);
}
if(!$sqlre->execute()) {
if(isset($this->conn->error_list[0]['error'])) $this->setSqlError($this->conn->error_list[0]['error']);
else $this->setSqlError('Unable to execute the SQL query, check if values are passed to sqlExec()');
}
}
else if($this->conn_mod == 'pdo'){
try { $sqlre->execute($param); }
catch(PDOException $e) { $this->setSqlError($e->getMessage()); }
}
$this->nr_queries++; // to know number of sql queries
}
else {
if(isset($this->conn->error_list[0]['error'])) $this->setSqlError($this->conn->error_list[0]['error']);
else $this->setSqlError('Unable to prepare the SQL query, check if SQL query data are correctly');
}
// if no error
if($this->error === false) {
// if $mode is 'select' or 'show', gets the result_set to return
if($mode == 'select' || $mode == 'show') {
$re = ($this->conn_mod == 'mysqli') ? $this->getSelectMySQLi($sqlre) : $this->getSelectPDO($sqlre); // gets select results
//set number of rows and items
$nr_i = count($re); // number of items in results
if(isset($re[0])) { $nr_i2 = ($this->fetch != 'assoc' && $this->fetch != 'num') ? count($re[0]) /2 : count($re[0]); }
else $nr_i2 =0;
if($this->group !='cols') {$this->num_rows = $nr_i; $this->num_cols = $nr_i2;}
else {$this->num_rows = $nr_i2; $this->num_cols = $nr_i;}
}
else { $re = true; $this->affected_rows = ($this->conn_mod == 'mysqli') ? $sqlre->affected_rows : $sqlre->rowCount(); } // affected rows for Insert, Update, Delete
// if Insert query, stores the last insert ID
if($mode == 'insert') $this->last_insertid = ($this->conn_mod == 'mysqli') ? $this->conn->insert_id : $this->conn->lastInsertId();
}
}
// sets to return false in case of error
if($this->error !== false) $re = false;
return $re;
}
// gets and returns Select results performed with PDO
// receives the object created with prepare() statement
protected function getSelectPDO($sqlre) {
$re = [];
// if fetch() returns at least one row (not false), adds the rows in $re, according to $fetch property
$fetch = $this->fetch =='assoc' ? PDO::FETCH_ASSOC :($this->fetch =='num' ? PDO::FETCH_NUM : PDO::FETCH_BOTH);
if($row = $sqlre->fetch($fetch)){
do {
// check each column if it has numeric value, to convert it from "string"
foreach($row AS $k=>$v){
if(is_numeric($v)) $row[$k] = $v + 0;
if($this->group =='cols'){ //store by cols
if(!isset($re[$k])) $re[$k] =[];
$re[$k][] = $v;
}
}
if($this->group !='cols') $re[] = $row; //store by rows
}
while($row = $sqlre->fetch($fetch));
}
return $re;
}
// gets and returns Select results performed with MySQLi
// receives the object created with prepare() statement
protected function getSelectMySQLi($sqlre) {
$re = [];
$result = $sqlre->get_result(); //get result set from a prepared /execute statement
// gets array with results according to $fetch
$fetch = $this->fetch =='assoc' ? MYSQLI_ASSOC :($this->fetch =='num' ? MYSQLI_NUM : MYSQLI_BOTH);
while($row = $result->fetch_array($fetch)){
if($this->group !='cols') $re[] = $row; //get by rows
else { //get by columns
foreach($row AS $k=>$v){
if(!isset($re[$k])) $re[$k] =[];
$re[$k][] = $v;
}
}
}
return $re;
}
// set sql error in $error
protected function setSqlError($err) {
$this->error = $err ;
}
}
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.some_class {
display: list-item;
}var obj = {
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};
var jsonstr = JSON.stringify(obj);
alert(jsonstr); // {"courses":["php","javascript","ajax"]}$strhtml = '<body><div id="dv1">CoursesWeb.net</div></body>';
$dochtml = new DOMDocument();
$dochtml->loadHTML($strhtml);
$elm = $dochtml->getElementById("dv1");
echo $elm->nodeValue; // CoursesWeb.net