PDO 增删改查封装的类

Selecting Data

这里写图片描述

你在mysql_*中是这样做的

1 <?php
2     $result = mysql_query('SELECT * from table') or die(mysql_error());
3 
4     $num_rows = mysql_num_rows($result);
5 
6     while($row = mysql_fetch_assoc($result)) {
7         echo $row['field1'];
8     }

你在pdo中可以这个样

<?php
    $stmt = $db->query('SELECT * FROM table');

    while($row = $stmt->fetch(PDO::FETCH_ASSOC)) {
        echo $row['field1'];
    }

或者

<?php
    $result = mysql_query('SELECT * from table') or die(mysql_error());

    $num_rows = mysql_num_rows($result);

    while($row = mysql_fetch_assoc($result)) {
        echo $row['field1'];
    }

提示：如果你使用了方法像query（）。这个方法返回一个PDOStatement 对象，如果你想取出结果，请这样使用：

<?php
    foreach($db->query('SELECT * FROM table') as $row) {
        echo $row['field1'];
    }

PDO数据是通过->fetch() 方法获得的，这个方法是你的statement处理的。 
在fetch之前。最好告诉PDO这个数据你打算怎么fetch。在下个章节我会解释。

Fetch Modes

PDO::FETCH_ASSOC 可以在fetch() 和 fetchAll()中使用。 这个告诉PDO返回关联数组，字段的名字作为key。这还有很多fench方法。

首先我说明怎么选择fench 模式。

$stmt->fetch(PDO::FETCH_ASSOC)

在这里我用的是fetch，你也可以用：

  • PDOStatement::fetchAll() 返回了一个数组包含了所有选择的行
  • PDOStatement::fetchColumn() 返回下一行的一列作为结果集
  • PDOStatement::fetchObject() 返回下一行作为一个对象
  • PDOStatement::setFetchMode() 设置fetch模式

下面讨论fetch模式

  • PDO::FETCH_ASSOC 关联数组
  • PDO::FETCH_BOTH 默认的。返回关联数组和索引数组。 
    还有更多选项，可以阅读文档。

获取行的数量 
不是通过mysql_num_rows 而是通过rowCount()，比如说：

<?php
    $stmt = $db->query('SELECT * FROM table');
    $row_count = $stmt->rowCount();
    echo $row_count.' rows selected';

获取插入的id

<?php
    $result = $db->exec("INSERT INTO table(firstname, lastname) VAULES('John', 'Doe')");
    $insertId = $db->lastInsertId();

Insert and Update or Delete statements

这里写图片描述

在mysql_*中我们是这样做的

<?php
    $results = mysql_query("UPDATE table SET field='value'") or die(mysql_error());
    echo mysql_affected_rows($result);

在PDO中，同样可以这样：

<?php
    $affected_rows = $db->exec("UPDATE table SET field='value'");
    echo $affected_rows;

在上面的语句中，执行了一个sql语句并且返回受影响的行数。

上面的方法在你查询语句中没有变量时很好用。如果有变量，就应该使用 prepared statement or parameterized statement 。

Prepared Statements

Q：什么是 Prepared Statements，我为什么要用他？

A：Prepared Statement 是一条预编译的sql语句，可以被执行多次。

典型的使用Prepared Statement 工作流：

  1. Prepare： 语句（statement）模版被application创建，发送到数据库管理系统（DBMS）。某些值仍然违背置顶，通过参数、占位符进行绑定
INSERT INTO PRODUCT (name, price) VALUES (?, ?)

  1. DBMS进行解析、编译，得到最优的语句，把结果（语句）储存起来，并不执行。

  2. 执行。过后，程序为参数提供或绑定值，DBMS执行语句（一般会返回一个结果）。程序或许会执行多次因为它有不同的值，想获得不同的结果。咱这个例子里，把Bread作为第一个参数，1.00作为第二个参数。

你可以通过引入占位符使用预编译语句。

Q：什么是命名占位符（named placeholders ），怎么使用呢？

A：命名占位符，用过一个冒号而不是？ 这样就不用去操心问号的顺序问题了

$stmt->bindParam(':bla', $bla);
<?php
    $stmt = $db->prepare("SELECT * FROM table WHERE id=:id AND name=:name");
    $stmt->execute(array(':name' => $name, ':id' => $id));
    $rows = $stmt->fetchAll(PDO::FETCH_ASSOC);

另一个对于OOP（面向对象编程）很友好的就是，命名占位符可以直接插入到你的对象，再然后加入到你的数据库。假设属性与字段相同

class person {
    public $name;
    public $add;
    function __construct($a,$b) {
        $this->name = $a;
        $this->add = $b;
    }

}
$demo = new person('john','29 bla district');
$stmt = $db->prepare("INSERT INTO table (name, add) value (:name, :add)");
$stmt->execute((array)$demo);

Q：好了，什么是匿名占位符(unnamed placeholders)，怎么使用？

A：看个例子。

<?php
    $stmt = $db->prepare("INSERT INTO folks (name, add) values (?, ?)");
    $stmt->bindValue(1, $name, PDO::PARAM_STR);
    $stmt->bindValue(2, $add, PDO::PARAM_STR);
    $stmt->execute();
$stmt = $db->prepare("INSERT INTO folks (name, add) values (?, ?)");
 $stmt->execute(array('john', '29 bla district'));

　　

注意：在匿名占位符我们一定要注意在数组中的顺序，在PDOStatement::execute() 方法中。

SELECT, INSERT, UPDATE, DELETE prepared queries

  1. select
$stmt = $db->prepare("SELECT * FROM table WHERE id=:id AND name=:name");
$stmt->execute(array(':name' => $name, ':id' => $id));
$rows = $stmt->fetchAll(PDO::FETCH_ASSOC);
  1. insert
$stmt = $db->prepare("INSERT INTO table(field1,field2) VALUES(:field1,:field2)");
$stmt->execute(array(':field1' => $field1, ':field2' => $field2));
$affected_rows = $stmt->rowCount();
  1. delete
$stmt = $db->prepare("DELETE FROM table WHERE id=:id");
$stmt->bindValue(':id', $id, PDO::PARAM_STR);
$stmt->execute();
$affected_rows = $stmt->rowCount();
  1. update
$stmt = $db->prepare("UPDATE table SET name=? WHERE id=?");
$stmt->execute(array($name, $id));
$affected_rows = $stmt->rowCount();

注意：

PDO和Mysqli也不是完全的安全。有机会会翻译一遍这个文章，这里就简单说一下：

$pdo->setAttribute(PDO::ATTR_EMULATE_PREPARES, false);
$pdo->query('SET NAMES GBK');
$stmt = $pdo->prepare("SELECT * FROM test WHERE name = ? LIMIT 1");
$stmt->execute(array(chr(0xbf) . chr(0x27) . " OR 1=1 /*"));

下面是一个封装的类

  1 class CPdo{
  2  protected $_dsn = "mysql:host=localhost;dbname=test";
  3  protected $_name = "root";
  4  protected $_pass = "";
  5  protected $_condition = array();
  6  protected $pdo;
  7  protected $fetchAll;
  8  protected $query;
  9  protected $result;
 10  protected $num;
 11  protected $mode;
 12  protected $prepare;
 13  protected $row;
 14  protected $fetchAction;
 15  protected $beginTransaction;
 16  protected $rollback;
 17  protected $commit;
 18  protected $char;
 19  private static $get_mode;
 20  private static $get_fetch_action;
 21  /**
 22  *pdo construct
 23  */
 24  public function __construct($pconnect = false) {
 25   $this->_condition = array(PDO::ATTR_PERSISTENT => $pconnect);
 26   $this->pdo_connect();
 27  }
 28  /**
 29  *pdo connect
 30  */
 31  private function pdo_connect() {
 32   try{
 33    $this->pdo = new PDO($this->_dsn,$this->_name,$this->_pass,$this->_condition);
 34   }
 35   catch(Exception $e) {
 36    return $this->setExceptionError($e->getMessage(), $e->getline, $e->getFile);
 37   }
 38  }
 39  /**
 40  *self sql get value action
 41  */
 42  public function getValueBySelfCreateSql($sql, $fetchAction = "assoc",$mode = null) {
 43   $this->fetchAction = $this->fetchAction($fetchAction);
 44   $this->result = $this->setAttribute($sql, $this->fetchAction, $mode);
 45   $this->AllValue = $this->result->fetchAll();
 46   return $this->AllValue;
 47  }
 48  /**
 49  *select condition can query
 50  */
 51  private function setAttribute($sql, $fetchAction, $mode) {
 52   $this->mode = self::getMode($mode);
 53   $this->fetchAction = self::fetchAction($fetchAction);
 54   $this->pdo->setAttribute(PDO::ATTR_CASE, $this->mode);
 55   $this->query = $this->base_query($sql);
 56   $this->query->setFetchMode($this->fetchAction);
 57   return $this->query;
 58  }
 59  /**
 60  *get mode action
 61  */
 62  private static function getMode($get_style){
 63   switch($get_style) {
 64    case null:
 65     self::$get_mode = PDO::CASE_NATURAL;
 66    break;
 67    case true:
 68     self::$get_mode = PDO::CASE_UPPER;
 69    break;
 70    case false;
 71    self::$get_mode= PDO::CASE_LOWER;
 72    break;
 73   }
 74   return self::$get_mode;
 75  }
 76  /**
 77  *fetch value action
 78  */
 79  private static function fetchAction($fetchAction) {
 80   switch($fetchAction) {
 81    case "assoc":
 82     self::$get_fetch_action = PDO::FETCH_ASSOC; //asso array
 83    break;
 84    case "num":
 85     self::$get_fetch_action = PDO::FETCH_NUM; //num array
 86    break;
 87    case "object":
 88     self::$get_fetch_action = PDO::FETCH_OBJ; //object array
 89    break;
 90    case "both":
 91     self::$get_fetch_action = PDO::FETCH_BOTH; //assoc array and num array
 92    break;
 93    default:
 94     self::$get_fetch_action = PDO::FETCH_ASSOC;
 95    break;
 96   }
 97   return self::$get_fetch_action;
 98  }
 99  /**
100  *get total num action
101  */
102  public function rowCount($sql) {
103   $this->result = $this->base_query($sql);
104   $this->num = $this->result->rowCount();
105   return $this->num;
106  }
107  /*
108  *simple query and easy query action
109  */
110  public function query($table, $column = "*",$condition = array(), $group = "",$order = "", $having = "", $startSet = "",$endSet = "",$fetchAction = "assoc",$params = null){
111   $sql = "select ".$column." from `".$table."` ";
112   if ($condition != null) {
113    foreach($condition as $key=>$value) {
114     $where .= "$key = '$value' and ";
115    }
116    $sql .= "where $where";
117    $sql .= "1 = 1 ";
118   }
119   if ($group != "") {
120    $sql .= "group by ".$group." ";
121   }
122   if ($order != "") {
123    $sql .= " order by ".$order." ";
124   }
125   if ($having != "") {
126    $sql .= "having '$having' ";
127   }
128   if ($startSet != "" && $endSet != "" && is_numeric($endSet) && is_numeric($startSet)) {
129    $sql .= "limit $startSet,$endSet";
130   }
131   $this->result = $this->getValueBySelfCreateSql($sql, $fetchAction, $params);
132   return $this->result;
133  }
134  /**
135  *execute delete update insert and so on action
136  */
137  public function exec($sql) {
138   $this->result = $this->pdo->exec($sql);
139   $substr = substr($sql, 0 ,6);
140   if ($this->result) {
141    return $this->successful($substr);
142   } else {
143    return $this->fail($substr);
144   }
145  }
146  /**
147  *prepare action
148  */
149  public function prepare($sql) {
150   $this->prepare = $this->pdo->prepare($sql);
151   $this->setChars();
152   $this->prepare->execute();
153   while($this->rowz = $this->prepare->fetch()) {
154    return $this->row;
155   }
156  }
157  /**
158  *USE transaction
159  */
160  public function transaction($sql) {
161   $this->begin();
162   $this->result = $this->pdo->exec($sql);
163   if ($this->result) {
164    $this->commit();
165   } else {
166    $this->rollback();
167   }
168  }
169  /**
170  *start transaction
171  */
172  private function begin() {
173   $this->beginTransaction = $this->pdo->beginTransaction();
174   return $this->beginTransaction;
175  }
176  /**
177  *commit transaction
178  */
179  private function commit() {
180   $this->commit = $this->pdo->commit();
181   return $this->commit;
182  }
183  /**
184  *rollback transaction
185  */
186  private function rollback() {
187   $this->rollback = $this->pdo->rollback();
188   return $this->rollback;
189  }
190  /**
191  *base query
192  */
193  private function base_query($sql) {
194   $this->setChars();
195   $this->query = $this->pdo->query($sql);
196   return $this->query;
197  }
198  /**
199  *set chars
200  */
201  private function setChars() {
202   $this->char = $this->pdo->query("SET NAMES 'UTF8'");
203   return $this->char;
204  }
205  /**
206  *process sucessful action 
207  */
208  private function successful($params){
209   return "The ".$params." action is successful";
210  }
211  /**
212  *process fail action
213  */
214  private function fail($params){
215   return "The ".$params." action is fail";
216  }
217  /***进程异常动作
218  *process exception action
219  */
220  private function setExceptionError($getMessage, $getLine ,$getFile) {
221   echo "Error message is ".$getMessage."<br /> The Error in ".$getLine." line <br /> This file dir on ".$getFile;
222   exit();
223  }
224 }

封装类2

  1 <?php
  2 /**
  3  */
  4 
  5 //使用pdo连接数据库 封装增删改查
  6 
  7 class DB{
  8 
  9 //定义私有属性
 10 private $host;
 11 private $port;
 12 private $username;
 13 private $password;
 14 private $dbname;
 15 private $charset;
 16 private $dbtype;
 17 private $pdo;
 18 
 19 //定义构造函数自动加载配置文件
 20 function __construct(){
 21 //加载配置文件
 22 include_once('./config/config.php');
 23 
 24 //给属性赋值
 25 $this->dbtype = $config['db'];
 26         $this->host  = $config['host'];
 27         $this->username = $config['username'];
 28         $this->password = $config['password'];
 29         $this->charset = $config['charset'];
 30         $this->port = $config['port'];
 31         $this->dbname = $config['dbname'];
 32 
 33 //pdo连接数据库
 34 $this->pdo = new PDO("$this->dbtype:host=$this->host;dbname=$this->dbname","$this->username","$this->password");
 35 //发送编码
 36 $this->pdo->query("set names $this->charset");
 37     }
 38 
 39 /**
 40      *   定义执行查询sql语句的方法
 41      *   参数： 查询sql语句
 42      *   返回： 二维关联数组
 43      */
 44 public function query($sql){
 45         $res = $this->pdo->query($sql);
 46         $res->setFetchMode(PDO::FETCH_ASSOC);
 47         $arr = $res->fetchAll();
 48 return $arr;
 49     }
 50 
 51 
 52 /**
 53      *   查询一行记录的方法
 54      *   参数：表名  条件(不包含where)
 55      *   返回：一维关联数组
 56      */
 57 public function getRow($tablename,$where){
 58 //组装sql语句
 59 $sql = "select * from $tablename where $where";
 60 //查询
 61 $res = $this->pdo->query($sql);
 62         $res->setFetchMode(PDO::FETCH_ASSOC);
 63         $arr = $res->fetch();
 64 return $arr;
 65     }
 66 
 67 
 68 /**
 69      *   查询全部记录
 70      *   参数：表名
 71      *   返回：二维关联数组
 72      */
 73 public function getAll($tablename){
 74         $res = $this->pdo->query("select * from $tablename");
 75         $res->setFetchMode(PDO::FETCH_ASSOC);
 76         $arr = $res->fetchAll();
 77 return $arr;
 78     }
 79 
 80 /**
 81      *   查询某个字段
 82      *   参数： 字段名(多个的话用逗号隔开) 表名 条件（不含where）
 83      *   返回： 二维关联数组
 84      */
 85 public function getOne($column,$tablename,$where="1"){
 86 //拼接sql语句
 87 $sql = "select $column from $tablename where $where";
 88         $rs = $this->pdo->query($sql);
 89         $rs->setFetchMode(PDO::FETCH_ASSOC);
 90 //$col = $rs->fetchColumn();
 91 $col = $rs->fetchAll();
 92 return  $col;
 93     }
 94 
 95 
 96 /**
 97      *   查询最后一次插入的数据
 98      *   参数：表名
 99      *   返回：数组
100     */
101 public function getlastone($tablename){
102         $sql = "select * from $tablename where id=(select max(id) from $tablename)";
103         $res = $this->pdo->query($sql);
104         $res->setFetchMode(PDO::FETCH_ASSOC);
105         $arr = $res->fetch();
106 return $arr;
107     }
108 
109 
110 /**
111      *  向数据库中添加一条信息
112      *  参数：表名 一维关联数组
113      *  返回: 布尔值
114      */
115 public function insert($tablename,$arr){
116 //拿到数组之后先处理数组  过滤字段
117         //取出表中的字段
118 $sql = "select COLUMN_NAME from information_schema.COLUMNS where table_name = '$tablename' and table_schema ='$this->dbname'";
119         $columns = $this->pdo->query($sql);
120         $columns->setFetchMode(PDO::FETCH_ASSOC);
121         $columns = $columns->fetchAll();
122         $cols = array(); //存储表中的全部字段
123 foreach($columns as $key=>$val){
124             $cols[] = $val['COLUMN_NAME'];
125         }
126 //将要入库的数组进行键值分离
127 $keys = array();
128         $values = '';
129 foreach($arr as $k=>$v){
130 if(!in_array($k,$cols)){
131 unset($arr[$k]);
132             }else{
133                 $keys[] = $k;
134                 $values .= "'".$v."',";
135             }
136         }
137         $column = implode(',',$keys);
138         $values = substr($values,0,-1);
139 //拼接sql语句
140 $sql = "insert into $tablename($column) values ($values)";
141         $res = $this->pdo->exec($sql);
142 return $res;
143     }
144 
145 
146 /**
147      *   删除数据 其实就是改变字段值使之不被查询
148      *   参数：表名 条件(不含where)
149      *   返回：布尔
150     */
151 public function delete($tablename,$where){
152         $sql = "update $tablename set is_del=1 where $where";
153         $res = $this->pdo->exec($sql);
154 return $res;
155     }
156 
157 
158 /**
159      *   修改数据
160      *   参数：表名  要修改的数据的数组
161      *   返回：布尔
162     */
163 public function update($tablename,$arr,$where){
164 //处理传过来的数组
165 $str = "";
166 foreach($arras $k=>$v){
167             $str .= "$k='".$v."',";
168         }
169 //截取字符串
170 $str = substr($str,0,-1);
171 //拼接sql语句
172 $sql = "update $tablename set $str where $where";
173         $res = $this->pdo->exec($sql);
174 return $res;
175     }
176 }
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原文地址：https://www.cnblogs.com/endv/p/8583405.html