PHP简单数据库操作类实例【支持增删改查及链式操作】

/**** @Authot: summer** @E-mail: wenghang1228@me.com** @Data: 2015-02-06** @Project: 数据库操作类Model** @Version:1.0** @版权所有：夏天的风————记录夏天对技术的追求与生活的热爱** @网址: http://www.xtwind.com**/class Model{  public $field;  public $tabname;  public $where;  public $order;  public $limit;  //构造函数，链接数据库，给表赋值  function __construct($tabname){    mysql_connect(HOST,USER,PASSWORD);    mysql_select_db(DBNAME);    mysql_query("set names utf8");    $this->tabname=$tabname;  }  //组合字段  function field($field){    $this->$field=$field;    return $this;  }  //组合where条件  function where($where){    $this->where="where ".$where;    return $this;  }  //组合order排序条件  function order($order){    $this->order="order by ".$order;    return $this;  }  //组合limit限制条数  function limit($limit){    $this->limit="limit ".$limit;    return $this;  }  //组合和执行select语句  function select($all=""){    if ($all) {      $sql="select {$all} from {$this->tabname} order by id";    }else{      $sql="select {$this->filed} from {$this->tabname} {$this->where} {$this->order} {$this->limit}";    }    $rst=mysql_query($sql);    while ($row=mysql_fetch_assoc($rst)) {      $rows[]=$row;    }    return $rows;  }  //组合和执行insert语句  function insert($post){ //数据库插入操作,接收数组    foreach ($post as $key => $value) {      $keys[]=$key;      $vals[]="'".$valu."'";    }    $keyStr=join(",",$keys);    $valStr=join(",",$vals);    $sql="insert into {$this->tabname}($keystr) values()";    if (mysql_query($sql)) {      return mysql_insert_id();    }else{      return false;    }  }  //组合和执行delect语句  function delect(){    $sql="delect from {$this->tabname} {$this->where}";    if (mysql_query($sql)) {      return mysql_affected_rows();    }else{      return false;    }  }  //组合和执行updata语句  function update($post){    foreach ($psot as $key => $value) {      $sets[]="{$key}='{$val}'";    }    $setStr=join(",",$sets);    $sql="update {$this->tabname} set {$setStr} {$this->where} ";    if (mysql_query($sql)) {      return mysql_affected_rows();    }else{      return false;    }  }  //从表中取一行数据  function find(){     if ($this->order) {      $sql="select * from {$this->tabname} {$this->order} limit 1";    }else{      $sql="select * from {$this->tabname} order by id limit 1";    }    $rst=mysql_query($sql);    while ($row=mysql_fetch_assoc($rst)) {      $rows[]=$row;    }    return $rows;  }  //获取总行数  function total(){     $sql="select count(*) from {$this->tabname}";    $rst=mysql_query($sql);    if ($rst) {      $row=mysql_fetch_row($rst);      return $row[0];    }else{      return false;    }  }}//Model类对象工厂function M($tabname){  return new Model($tabname);}define("HOST","localhost");define("USER", "root");define("PASSWORD", "123456");define("DBNAME", "test")$user=new Model("user");$user->field("id,name")->where("id=3")->order("id desc")->limit("3")->select();