PHP database operation base class implemented based on singleton mode

The example in this article describes the database operation base class implemented by PHP based on the singleton mode. Share it with everyone for your reference, the details are as follows:

Configuration file:

<&#63;php
$db = array(
    'host'=>'localhost',
    'user'=>'root',
    'password'=>'',
    'database'=>'test',
)
?>

php Database base class:

<&#63;php
class db {
  public $conn;
  public static $sql;
  public static $instance=null;
  private function __construct(){
    require_once('db.config.php');
    $this->conn = mysql_connect($db['host'],$db['user'],$db['password']);
    if(!mysql_select_db($db['database'],$this->conn)){
      echo "失败";
    };
    mysql_query('set names utf8',$this->conn);
  }
  public static function getInstance(){
    if(is_null(self::$instance)){
      self::$instance = new db;
    }
    return self::$instance;
  }
  /**
   * 查询数据库
   */
  public function select($table,$c = array()){
    $where='';
    if(!empty($condition)){
      foreach($condition as $k=>$v){
        $where.=$k."='".$v."' and ";
      }
      $where='where '.$where .'1=1';
    }
    $fieldstr = '';
    if(!empty($field)){
      foreach($field as $k=>$v){
        $fieldstr.= $v.',';
      }
       $fieldstr = rtrim($fieldstr,',');
    }else{
      $fieldstr = '*';
    }
    self::$sql = "select {$fieldstr} from {$table} {$where}";
    $result=mysql_query(self::$sql,$this->conn);
    $resuleRow = array();
    $i = 0;
    while($row=mysql_fetch_assoc($result)){
      foreach($row as $k=>$v){
        $resuleRow[$i][$k] = $v;
      }
      $i++;
    }
    return $resuleRow;
  }
  /**
   * 添加一条记录
   */
   public function insert($table,$data){
    $values = '';
    $datas = '';
    foreach($data as $k=>$v){
      $values.=$k.',';
      $datas.="'$v'".',';
    }
    $values = rtrim($values,',');
    $datas  = rtrim($datas,',');
    self::$sql = "INSERT INTO {$table} ({$values}) VALUES ({$datas})";
    if(mysql_query(self::$sql)){
      return mysql_insert_id();
    }else{
      return false;
    };
   }
   /**
   * 修改一条记录
   */
  public function update($table,$data,$c
    $where='';
    if(!empty($condition)){
      foreach($condition as $k=>$v){
        $where.=$k."='".$v."' and ";
      }
      $where='where '.$where .'1=1';
    }
    $updatastr = '';
    if(!empty($data)){
      foreach($data as $k=>$v){
        $updatastr.= $k."='".$v."',";
      }
      $updatastr = 'set '.rtrim($updatastr,',');
    }
    self::$sql = "update {$table} {$updatastr} {$where}";
    return mysql_query(self::$sql);
  }
  /**
   * 删除记录
   */
   public function delete($table,$condition){
    $where='';
    if(!empty($condition)){
      foreach($condition as $k=>$v){
        $where.=$k."='".$v."' and ";
      }
      $where='where '.$where .'1=1';
    }
    self::$sql = "delete from {$table} {$where}";
    return mysql_query(self::$sql);
   }
  public static function getLastSql(){
    echo self::$sql;
  }
}
$db = db::getInstance();
//$list = $db->select('demo',array('name'=>'tom','password'=>'ds'),array('name','password'));
//echo $db->insert('demo',array('name'=>'本站','password'=>'123'));
//echo $db->update('demo',array("name"=>'xxx',"password"=>'123'),array('id'=>1));
echo $db->delete('demo',array('id'=>'2'));
db::getLastSql();
echo "<pre class="brush:php;toolbar:false">";
?>

Readers who are interested in more content related to PHP operation database can check out the special topic of this site: "php +MySQL database operation introductory tutorial", "PHP based on pdo database operation skills summary" and "php common database operation skills summary"

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