PHP encapsulated MSSql operation class and complete example analysis

<?php
/*MSSql的操作类*/
class MSSql {
  var $link;
  var $querynum = 0;
  /*连接MSSql数据库，参数：dbsn->数据库服务器地址，dbun->登陆用户名，dbpw->登陆密码，dbname->数据库名字*/
  function Connect($dbsn, $dbun, $dbpw, $dbname) {
    if($this->link = @mssql_connect($dbsn, $dbun, $dbpw, true)) {
      $query = $this->Query(&#39;SET TEXTSIZE 2147483647&#39;);
      if (@mssql_select_db($dbname, $this->link)) {
      } else {
        $this->halt(&#39;Can not Select DataBase&#39;);
      }
    } else {
      $this->halt(&#39;Can not connect to MSSQL server&#39;);
    }
  }
  /*执行sql语句，返回对应的结果标识*/
  function Query($sql) {
    if($query = @mssql_query($sql, $this->link)) {
      $this->querynum++;
      return $query;
    } else {
      $this->querynum++;
      $this->halt(&#39;MSSQL Query Error&#39;, $sql);
    }
  }
  /*执行Insert Into语句，并返回最后的insert操作所产生的自动增长的id*/
  function Insert($table, $iarr) {
    $value = $this->InsertSql($iarr);
    $query = $this->Query(&#39;INSERT INTO &#39; . $table . &#39; &#39; . $value . &#39;; SELECT SCOPE_IDENTITY() AS [insertid];&#39;);
    $record = $this->GetRow($query);
    $this->Clear($query);
    return $record[&#39;insertid&#39;];
  }
  /*执行Update语句，并返回最后的update操作所影响的行数*/
  function Update($table, $uarr, $condition = &#39;&#39;) {
    $value = $this->UpdateSql($uarr);
    if ($condition) {
      $condition = &#39; WHERE &#39; . $condition;
    }
    $query = $this->Query(&#39;UPDATE &#39; . $table . &#39; SET &#39; . $value . $condition . &#39;; SELECT @@ROWCOUNT AS [rowcount];&#39;);
    $record = $this->GetRow($query);
    $this->Clear($query);
    return $record[&#39;rowcount&#39;];
  }
  /*执行Delete语句，并返回最后的Delete操作所影响的行数*/
  function Delete($table, $condition = &#39;&#39;) {
    if ($condition) {
      $condition = &#39; WHERE &#39; . $condition;
    }
    $query = $this->Query(&#39;DELETE &#39; . $table . $condition . &#39;; SELECT @@ROWCOUNT AS [rowcount];&#39;);
    $record = $this->GetRow($query);
    $this->Clear($query);
    return $record[&#39;rowcount&#39;];
  }
  /*将字符转为可以安全保存的mssql值，比如a&#39;a转为a&#39;&#39;a*/
  function EnCode($str) {
    return str_replace(&#39;&#39;&#39;, &#39;&#39;&#39;&#39;, str_replace(&#39;&#39;, &#39;&#39;, $str));
  }
  /*将可以安全保存的mssql值转为正常的值，比如a&#39;&#39;a转为a&#39;a*/
  function DeCode($str) {
    return str_replace(&#39;&#39;&#39;&#39;, &#39;&#39;&#39;, $str);
  }
  /*将对应的列和值生成对应的insert语句，如：array(&#39;id&#39; => 1, &#39;name&#39; => &#39;name&#39;)返回([id], [name]) VALUES (1, &#39;name&#39;)*/
  function InsertSql($iarr) {
    if (is_array($iarr)) {
      $fstr = &#39;&#39;;
      $vstr = &#39;&#39;;
      foreach ($iarr as $key => $val) {
        $fstr .= &#39;[&#39; . $key . &#39;], &#39;;
        $vstr .= &#39;&#39;&#39; . $val . &#39;&#39;, &#39;;
      }
      if ($fstr) {
        $fstr = &#39;(&#39; . substr($fstr, 0, -2) . &#39;)&#39;;
        $vstr = &#39;(&#39; . substr($vstr, 0, -2) . &#39;)&#39;;
        return $fstr . &#39; VALUES &#39; . $vstr;
      } else {
        return &#39;&#39;;
      }
    } else {
      return &#39;&#39;;
    }
  }
  /*将对应的列和值生成对应的insert语句，如：array(&#39;id&#39; => 1, &#39;name&#39; => &#39;name&#39;)返回[id] = 1, [name] = &#39;name&#39;*/
  function UpdateSql($uarr) {
    if (is_array($uarr)) {
      $ustr = &#39;&#39;;
      foreach ($uarr as $key => $val) {
        $ustr .= &#39;[&#39; . $key . &#39;] = &#39;&#39; . $val . &#39;&#39;, &#39;;
      }
      if ($ustr) {
        return substr($ustr, 0, -2);
      } else {
        return &#39;&#39;;
      }
    } else {
      return &#39;&#39;;
    }
  }
  /*返回对应的查询标识的结果的一行*/
  function GetRow($query, $result_type = MSSQL_ASSOC) {
    return mssql_fetch_array($query, $result_type);
  }
  /*清空查询结果所占用的内存资源*/
  function Clear($query) {
    return mssql_free_result($query);
  }
  /*关闭数据库*/
  function Close() {
    return mssql_close($this->link);
  }
  function halt($message = &#39;&#39;, $sql = &#39;&#39;) {
    $message .= &#39;<br />MSSql Error:&#39; . mssql_get_last_message();
    if ($sql) {
      $sql = &#39;<br />sql:&#39; . $sql;
    }
    exit("DataBase Error.<br />Message $message $sql");
  }
}
?>