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A singleton mode Mysql operation class encapsulated by PHP plays an important role in PHP. This article will explain its related knowledge in detail.
A singleton mode Mysql operation class encapsulated by PHP
Master the necessary conditions to meet the singleton mode----three private and one public.
①Private construction method-to prevent the use of the new keyword to instantiate objects outside the class.
②Private member attributes-in order to prevent the attributes of storing objects from being introduced outside the class.
③Private clone method-in order to prevent another object from being cloned outside the class.
④Public static methods-to allow users to instantiate objects.
DB class and related table operations;
class mysql_db{ //1.私有的静态属性 private static $dbcon = false; //2.私有的构造方法 private function __construct(){ $dbconn = @mysql_connect("localhost","root",""); mysql_select_db("test",$dbconn) or die("mysql_connect error"); mysql_query("SET NAMES utf8"); } //3.私有的克隆方法 private function __clone() { } //1.公有的静态方法 public static function getIntance() { if(self::$dbcon==false){ self::$dbcon=new self; } return self::$dbcon; } //执行语句 public function query($sql) { $query=mysql_query($sql); return $query; } /** * 查询某个字段 * @param * @return string or int */ public function getOne($sql) { $query = $this->query($sql); return mysql_result($query,0); } //获取一行记录,return array 一维数组 public function getRow($sql,$type="assoc") { $query=$this->query($sql); if(!in_array($type,array("assoc",'array',"row"))) { die("mysql_query error"); } $funcname = "mysql_fetch_".$type; return $funcname($query); } //获取一条记录,前置条件通过资源获取一条记录 public function getFormSource($query,$type="assoc"){ if(!in_array($type,array("assoc","array","row"))) { die("mysql_query error"); } $funcname = "mysql_fetch_".$type; return $funcname($query); } //获取多条数据,二维数组 public function getAll($sql){ $query=$this->query($sql); $list=array(); while ($r=$this->getFormSource($query)) { $list[]=$r; } return $list; } //获得最后一条记录id public function getInsertid(){ return mysql_insert_id(); } /** * 定义添加数据的方法 * @param string $table 表名 * @param string orarray $data [数据] * @return int 最新添加的id */ public function insert($table,$data){ //遍历数组,得到每一个字段和字段的值 $key_str=''; $v_str=''; foreach($data as $key=>$v) { if(empty($v)) { die("error"); } //$key的值是每一个字段s一个字段所对应的值 $key_str.=$key.','; $v_str.="'$v',"; } $key_str=trim($key_str,','); $v_str=trim($v_str,','); //判断数据是否为空 $sql="insert into $table ($key_str) values ($v_str)"; $this->query($sql); //返回上一次增加操做产生ID值 return mysql_insert_id(); } /* * 删除一条数据方法 * @param1 $table, $where=array('id'=>'1') 表名 条件 * @return 受影响的行数 */ public function deleteOne($table, $where){ if(is_array($where)){ foreach ($where as $key => $val) { $condition = $key.'='.$val; } } else { $condition = $where; } $sql = "delete from $table where $condition"; $this->query($sql); //返回受影响的行数 return mysql_affected_rows(); } /* * 删除多条数据方法 * @param1 $table, $where 表名 条件 * @return 受影响的行数 */ public function deleteAll($table, $where){ if(is_array($where)){ foreach ($where as $key => $val) { if(is_array($val)){ $condition = $key.' in ('.implode(',', $val) .')'; } else { $condition = $key. '=' .$val; } } } else { $condition = $where; } $sql = "delete from $table where $condition"; $this->query($sql); //返回受影响的行数 return mysql_affected_rows(); } /** * [修改操作description] * @param [type] $table [表名] * @param [type] $data [数据] * @param [type] $where [条件] * @return [type] */ public function update($table,$data,$where) { //遍历数组,得到每一个字段和字段的值 $str=''; foreach($data as $key=>$v){ $str.="$key='$v',"; } $str=rtrim($str,','); //修改SQL语句 $sql="update $table set $str where $where"; $this->query($sql); //返回受影响的行数 return mysql_affected_rows(); } }
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