Sample code for adding, deleting, modifying and querying the database using PDO method in PHP

PDO is a public class for mysql database operation. We can directly use pdo to operate the database without customizing the class. However, in the default configuration of php, pdo is not enabled, so we must You need to enable it in php.ini before you can use it.

You need to enable php's pdo support, php5.1 or above supports it

realizes singletonization of database connection, which has three elements: static variables, static instantiation methods, and private constructor DPDO.php

class DPDO{
  private $DSN;
  private $DBUser;
  private $DBPwd;
  private $longLink;
  private $pdo;
  //私有构造函数 防止被直接实例化
  private function construct($dsn, $DBUser, $DBPwd, $longLink = false) {
    $this->DSN = $dsn;
    $this->DBUser = $DBUser;
    $this->DBPwd = $DBPwd;
    $this->longLink = $longLink;
    $this->connect();
  }
  //私有 空克隆函数 防止被克隆
  private function clone(){}
  //静态 实例化函数 返回一个pdo对象
  static public function instance($dsn, $DBUser, $DBPwd, $longLink = false){
    static $singleton = array();//静态函数 用于存储实例化对象
    $singIndex = md5($dsn . $DBUser . $DBPwd . $longLink);
    if (empty($singleton[$singIndex])) {
      $singleton[$singIndex] = new self($dsn, $DBUser, $DBPwd, $longLink = false);
    }
    return $singleton[$singIndex]->pdo;
  }
   
  private function connect(){
    try{
      if($this->longLink){
        $this->pdo = new PDO($this->DSN, $this->DBUser, $this->DBPwd, array(PDO::ATTR_PERSISTENT => true));
      }else{
        $this->pdo = new PDO($this->DSN, $this->DBUser, $this->DBPwd);
      }
      $this->pdo->query('SET NAMES UTF-8');
    } catch(PDOException $e) {
      die(&#39;Error:&#39; . $e->getMessage() . &#39;<br/>&#39;);
    }
  }
}

is used to process field mapping. Using pdo field mapping can effectively avoid sql injection

//字段关联数组处理， 主要用于写入和更新数据、同and 或 or 的查询条件，产生sql语句和映射字段的数组
  public function FDFields($data, $link = ',', $judge = array(), $aliasTable = ''){
    $sql = '';
    $mapData = array();
    foreach($data as $key => $value) {
      $mapIndex = ':' . ($link != ',' ? 'c' : '') . $aliasTable . $key;
      $sql .= ' ' . ($aliasTable ? $aliasTable . '.' : '') . '`' . $key . '` ' . ($judge[$key] ? $judge[$key] : '=') . ' ' . $mapIndex . ' ' . $link;
      $mapData[$mapIndex] = $value;
    }
    $sql = trim($sql, $link);
    return array($sql, $mapData);
  }
  //用于处理单个字段处理
  public function FDField($field, $value, $judge = '=', $preMap = 'cn', $aliasTable = '') {
    $mapIndex = ':' . $preMap . $aliasTable . $field;
    $sql = ' ' . ($aliasTable ? $aliasTable . '.' : '') . '`' . $field . '`' . $judge . $mapIndex;
    $mapData[$mapIndex] = $value;
    return array($sql, $mapData);
  }
  //使用刚方法可以便捷产生查询条件及对应数据数组
  public function FDCondition($condition, $mapData) {
    if(is_string($condition)) {
        $where = $condition;
    } else if (is_array($condition)) {
      if($condition['str']) {
        if (is_string($condition['str'])) {
          $where = $condition['str'];
        } else {
          return false;
        }
      }
      if(is_array($condition['data'])) {
        $link = $condition['link'] ? $condition['link'] : 'and';
        list($conSql, $mapConData) = $this->FDFields($condition['data'], $link, $condition['judge']);
        if ($conSql) {
          $where .= ($where ? ' ' . $link : '') . $conSql;
          $mapData = array_merge($mapData, $mapConData);
        }
      }
    }
    return array($where, $mapData);
  }

The specific implementation of addition, deletion, modification and query DB.php

public function fetch($sql, $searchData = array(), $dataMode = PDO::FETCH_ASSOC, $preType = array(PDO::ATTR_CURSOR => PDO::CURSOR_FWDONLY)) {
    if ($sql) {
      $sql .= ' limit 1';
      $pdoStatement = $this->pdo->prepare($sql, $preType);
      $pdoStatement->execute($searchData);
      return $data = $pdoStatement->fetch($dataMode);
    } else {
      return false;
    }
  }
   
  public function fetchAll($sql, $searchData = array(), $limit = array(0, 10), $dataMode = PDO::FETCH_ASSOC, $preType = array(PDO::ATTR_CURSOR => PDO::CURSOR_FWDONLY)) {
    if ($sql) {
      $sql .= ' limit ' . (int) $limit[0] . ',' . (intval($limit[1]) > 0 ? intval($limit[1]) : 10);
      $pdoStatement = $this->pdo->prepare($sql, $preType);
      $pdoStatement->execute($searchData);
      return $data = $pdoStatement->fetchAll($dataMode);
    } else {
      return false;
    }
  }
   
  public function insert($tableName, $data, $returnInsertId = false, $replace = false) {
    if(!empty($tableName) && count($data) > 0){
      $sql = $replace ? 'REPLACE INTO ' : 'INSERT INTO ';
      list($setSql, $mapData) = $this->FDFields($data);
      $sql .= $tableName . ' set ' . $setSql;
      $pdoStatement = $this->pdo->prepare($sql, array(PDO::ATTR_CURSOR => PDO::CURSOR_FWDONLY));
      $execRet = $pdoStatement->execute($mapData);
      return $execRet ? ($returnInsertId ? $this->pdo->lastInsertId() : $execRet) : false;
    } else {
      return false;
    }
  }
   
  public function update($tableName, $data, $condition, $mapData = array(), $returnRowCount = true) {
    if(!empty($tableName) && count($data) > 0) {
      $sql = 'UPDATE ' . $tableName . ' SET ';
      list($setSql, $mapSetData) = $this->FDFields($data);
      $sql .= $setSql;
      $mapData = array_merge($mapData, $mapSetData);
      list($where, $mapData) = $this->FDCondition($condition, $mapData);
      $sql .= $where ? ' WHERE ' . $where : '';
      $pdoStatement = $this->pdo->prepare($sql, array(PDO::ATTR_CURSOR => PDO::CURSOR_FWDONLY));
      $execRet = $pdoStatement->execute($mapData);
      return $execRet ? ($returnRowCount ? $pdoStatement->rowCount() : $execRet) : false;
    } else {
      return false;
    }
  }
   
  public function delete($tableName, $condition, $mapData = array()) {
    if(!empty($tableName) && $condition){
      $sql = 'DELETE FROM ' . $tableName;
      list($where, $mapData) = $this->FDCondition($condition, $mapData);
      $sql .= $where ? ' WHERE ' . $where : '';
      $pdoStatement = $this->pdo->prepare($sql, array(PDO::ATTR_CURSOR => PDO::CURSOR_FWDONLY));
      $execRet = $pdoStatement->execute($mapData);
      return $execRet;
    }
  }

Test file test.php

header("Content-type: text/html; charset=utf-8");
define('APP_DIR', dirname(FILE));
 
if (function_exists('spl_autoload_register')) {
  spl_autoload_register('autoClass');
} else {
  function auto_load($className){
    autoClass($className);
  }
}
 
function autoClass($className){
  try{
    require_once APP_DIR.'/class/'.$className.'.php';
  } catch (Exception $e) {
    die(&#39;Error:&#39; . $e->getMessage() . &#39;<br />&#39;);
  }
}
$DB = new DB();
//插入
$inData[&#39;a&#39;] = rand(1, 100);
$inData[&#39;b&#39;] = rand(1, 1000);
$inData[&#39;c&#39;] = rand(1,200) . &#39;.&#39; . rand(1,100);
$ret = $DB->insert(&#39;a&#39;, $inData);
echo &#39;插入&#39; . ($ret ? &#39;成功&#39; : &#39;失败&#39;) . &#39;<br/>&#39;;
//更新
$upConData[&#39;a&#39;] = 100;
$upConJudge[&#39;a&#39;] = &#39;<&#39;;
$upConData[&#39;b&#39;] = 30;
$upConJudge[&#39;b&#39;] = &#39;>&#39;;
list($upConStr, $mapUpConData) = $DB->FDField(&#39;b&#39;, 200, &#39;<&#39;, &#39;gt&#39;);
$condition = array(
  &#39;str&#39; => $upConStr,
  &#39;data&#39; => $upConData,
  &#39;judge&#39; => $upConJudge,
  &#39;link&#39; => &#39;and&#39;
);
$upData[&#39;a&#39;] = rand(1, 10);
$upData[&#39;b&#39;] = 1;
$upData[&#39;c&#39;] = 1.00;
$changeRows = $DB->update(&#39;a&#39;, $upData, $condition, $mapUpConData);
echo &#39;更新行数:&#39; . (int) $changeRows . &#39;<br/>&#39;;
//删除
$delVal = rand(1, 10);
list($delCon, $mapDelCon) = $DB->FDField(&#39;a&#39;, $delVal);
$delRet = $DB->delete(&#39;a&#39;, $delCon, $mapDelCon);
echo &#39;删除a=&#39; . $delVal . ($delRet ? &#39;成功&#39; : &#39;失败&#39;) . &#39;<br/>&#39;;
 
//查询
$data[&#39;a&#39;] = &#39;10&#39;;
$judge[&#39;a&#39;] = &#39;>&#39;;
$data[&#39;b&#39;] = &#39;400&#39;;
$judge[&#39;b&#39;] = &#39;<&#39;;
list($conSql, $mapConData) = $DB->FDFields($data, &#39;and&#39;, $judge);
$mData = $DB->fetch(&#39;select * from a where &#39; . $conSql . &#39; order by `a` desc&#39;, $mapConData);
 
var_dump($mData);

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