php - 如何将mysql查询写入PDO

Question

如果您能帮我将下面的 mysql 代码写入 PDO 语句，我将不胜感激。

     $sql  = "SELECT * FROM node WHERE node_name='$nodename'";

     $result = mysql_query($sql);

当我阅读 PDO::query 手册时，我发现了这段代码

      <?php
      $connection = new pdo("sqlite:file.sq3");
      $query="SELECT * FROM table";
      $result = $connection->query($query);
      $row = $result->fetch(PDO::FETCH_ASSOC);
      print_r($row);
      ?>

“sqlite:file.sq3”和“(PDO::FETCH_ASSOC)”的函数是什么

Answer 1

您像这样连接到数据库:

try {
$db = new PDO("sqlite:file.sq3");
$db->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
    } catch (PDOException $e) {
       echo 'Error : <br>' . $e->getMessage();
}

PS: You dont need the try and the catch, but we used to get the error and handle it in a nice way as we want to

接下来我们像这样查询:

 $db->query(SELECT * FROM node WHERE node_name='$nodename'");

我们像这样获取它:

 $query = $db->query(SELECT * FROM node WHERE node_name='$nodename'");
 $row   = $query->fetch(PDO::FETCH_OBJ);

现在您使用 $row->name 例如

这里有更多关于 PDO::FETCH 的内容

• PDO::FETCH_ASSOC: returns an array indexed by column name as returned in your result set

• PDO::FETCH_BOTH (default): returns an array indexed by both column name and 0-indexed column number as returned in your result set

• PDO::FETCH_BOUND: returns TRUE and assigns the values of the columns in your result set to the PHP variables to which they were
  bound with the PDOStatement::bindColumn() method

• PDO::FETCH_CLASS: returns a new instance of the requested class, mapping the columns of the result set to named properties in the
  class. If fetch_style includes PDO::FETCH_CLASSTYPE (e.g.
  PDO::FETCH_CLASS | PDO::FETCH_CLASSTYPE) then the name of the class
  is determined from a value of the first column.

• PDO::FETCH_INTO: updates an existing instance of the requested class, mapping the columns of the result set to named properties in
  the class

• PDO::FETCH_LAZY: combines PDO::FETCH_BOTH and PDO::FETCH_OBJ, creating the object variable names as they are accessed

• PDO::FETCH_NUM: returns an array indexed by column number as returned in your result set, starting at column 0

• PDO::FETCH_OBJ: returns an anonymous object with property names that correspond to the column names returned in your result set