php mysql PDO使用，phpmysqlpdo使用

php mysql PDO使用，phpmysqlpdo使用

<span> 1</span> <?<span>php
</span><span> 2</span> <span>$dbh</span> = <span>new</span> PDO('mysql:host=localhost;dbname=access_control', 'root', ''<span>);  
</span><span> 3</span> <span>$dbh</span>->setAttribute(PDO::ATTR_ERRMODE, PDO::<span>ERRMODE_EXCEPTION);  
</span><span> 4</span> <span>$dbh</span>-><span>exec</span>('set names utf8'<span>); 
</span><span> 5</span> <span>/*</span><span>添加</span><span>*/</span>
<span> 6</span> <span>//</span><span>$sql = "INSERT INTO `user` SET `login`=:login AND `password`=:password"; </span>
<span> 7</span> <span>$sql</span> = "INSERT INTO `user` (`login` ,`password`)VALUES (:login, :password)";  <span>$stmt</span> = <span>$dbh</span>->prepare(<span>$sql</span>);  <span>$stmt</span>->execute(<span>array</span>(':login'=>'kevin2',':password'=>''<span>));  
</span><span> 8</span> <span>echo</span> <span>$dbh</span>-><span>lastinsertid();  
</span><span> 9</span> <span>/*</span><span>修改</span><span>*/</span>
<span>10</span> <span>$sql</span> = "UPDATE `user` SET `password`=:password WHERE `user_id`=:userId"<span>;  
</span><span>11</span> <span>$stmt</span> = <span>$dbh</span>->prepare(<span>$sql</span><span>);  
</span><span>12</span> <span>$stmt</span>->execute(<span>array</span>(':userId'=>'7', ':password'=>'4607e782c4d86fd5364d7e4508bb10d9'<span>));  
</span><span>13</span> <span>echo</span> <span>$stmt</span>-><span>rowCount(); 
</span><span>14</span> <span>/*</span><span>删除</span><span>*/</span>
<span>15</span> <span>$sql</span> = "DELETE FROM `user` WHERE `login` LIKE 'kevin_'"; <span>//</span><span>kevin%  </span>
<span>16</span> <span>$stmt</span> = <span>$dbh</span>->prepare(<span>$sql</span><span>);  
</span><span>17</span> <span>$stmt</span>-><span>execute();  
</span><span>18</span> <span>echo</span> <span>$stmt</span>-><span>rowCount();  
</span><span>19</span> <span>/*</span><span>查询</span><span>*/</span>
<span>20</span> <span>$login</span> = 'kevin%'<span>;  
</span><span>21</span> <span>$sql</span> = "SELECT * FROM `user` WHERE `login` LIKE :login"<span>;  
</span><span>22</span> <span>$stmt</span> = <span>$dbh</span>->prepare(<span>$sql</span><span>);  
</span><span>23</span> <span>$stmt</span>->execute(<span>array</span>(':login'=><span>$login</span><span>));  
</span><span>24</span> <span>while</span>(<span>$row</span> = <span>$stmt</span>->fetch(PDO::<span>FETCH_ASSOC)){     
</span><span>25</span>  <span>print_r</span>(<span>$row</span><span>);  
</span><span>26</span> <span>}  
</span><span>27</span> <span>print_r</span>( <span>$stmt</span>->fetchAll(PDO::<span>FETCH_ASSOC)); 
</span><span>28</span> ?>

1 建立连接

<span>1</span> <?<span>php
</span><span>2</span> <span>$dbh</span>=newPDO('mysql:host=localhost;port=3306; dbname=test',<span>$user</span>,<span>$pass</span>,<span>array</span><span>(
</span><span>3</span> PDO::ATTR_PERSISTENT=><span>true</span>
<span>4</span> <span>));
</span><span>5</span> ?>

持久性链接PDO::ATTR_PERSISTENT=>true

2. 捕捉错误

<span> 1</span> <?<span>php
</span><span> 2</span> <span>try</span><span>{
</span><span> 3</span> <span>$dbh</span>=newPDO('mysql:host=localhost;dbname=test',<span>$user</span>,<span>$pass</span><span>);
</span><span> 4</span> 
<span> 5</span> <span>$dbh</span>->setAttribute(PDO::ATTR_ERRMODE,PDO::<span>ERRMODE_EXCEPTION);
</span><span> 6</span> 
<span> 7</span> <span>$dbh</span>-><span>exec</span>("SET CHARACTER SET utf8"<span>);
</span><span> 8</span> <span>$dbh</span>=<span>null</span>; <span>//</span><span>断开连接</span>
<span> 9</span> }<span>catch</span>(PDOException<span>$e</span><span>){
</span><span>10</span> <span>print</span>"Error!:".<span>$e</span>->getMessage()."<br/>"<span>;
</span><span>11</span> <span>die</span><span>();
</span><span>12</span> <span>}
</span><span>13</span> ?>

3. 事务的

<span> 1</span> <?<span>php
</span><span> 2</span> <span>try</span><span>{
</span><span> 3</span> <span>$dbh</span>->setAttribute(PDO::ATTR_ERRMODE,PDO::<span>ERRMODE_EXCEPTION);
</span><span> 4</span> 
<span> 5</span> <span>$dbh</span>->beginTransaction();<span>//</span><span>开启事务</span>
<span> 6</span> <span>$dbh</span>-><span>exec</span>("insertintostaff(id,first,last)values(23,'Joe','Bloggs')"<span>);
</span><span> 7</span> <span>$dbh</span>-><span>exec</span>("<span>insertintosalarychange(id,amount,changedate)
</span><span> 8</span> values(23,50000,NOW())"<span>);
</span><span> 9</span> <span>$dbh</span>->commit();<span>//</span><span>提交事务</span>
<span>10</span> 
<span>11</span> }<span>catch</span>(<span>Exception</span><span>$e</span><span>){
</span><span>12</span> <span>$dbh</span>->rollBack();<span>//</span><span>错误回滚</span>
<span>13</span> <span>echo</span>"Failed:".<span>$e</span>-><span>getMessage();
</span><span>14</span> <span>}
</span><span>15</span> ?>

4. 错误处理

a. 静默模式(默认模式)

$dbh->setAttribute(PDO::ATTR_ERRMODE,PDO::ERRMODE_SILENT); //不显示错误

$dbh->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_WARNING);//显示警告错误，并继续执行

$dbh->setAttribute(PDO::ATTR_ERRMODE,PDO::ERRMODE_EXCEPTION);//产生致命错误，PDOException

<span> 1</span> <?<span>php
</span><span> 2</span> <span>try</span><span>{    
</span><span> 3</span>  <span>$dbh</span> = <span>new</span> PDO(<span>$dsn</span>, <span>$user</span>, <span>$password</span><span>);    
</span><span> 4</span>  <span>$sql</span> = 'Select * from city where CountryCode =:country'<span>;    
</span><span> 5</span>  <span>$dbh</span>->setAttribute(PDO::ATTR_ERRMODE, PDO::<span>ERRMODE_WARNING);    
</span><span> 6</span>  <span>$stmt</span> = <span>$dbh</span>->prepare(<span>$sql</span><span>);    
</span><span> 7</span>  <span>$stmt</span>->bindParam(':country', <span>$country</span>, PDO::<span>PARAM_STR);    
</span><span> 8</span>  <span>$stmt</span>-><span>execute();    
</span><span> 9</span>  <span>while</span> (<span>$row</span> = <span>$stmt</span>->fetch(PDO::<span>FETCH_ASSOC)) {      
</span><span>10</span>   <span>print</span> <span>$row</span>['Name'] . "/t"<span>;    
</span><span>11</span> <span> }  
</span><span>12</span> }   <span>//</span><span> if there is a problem we can handle it here  </span>
<span>13</span> <span>catch</span> (PDOException <span>$e</span><span>)  {    
</span><span>14</span>  <span>echo</span> 'PDO Exception Caught.  '<span>;    
</span><span>15</span>  <span>echo</span> 'Error with the database: <br />'<span>;    
</span><span>16</span>  <span>echo</span> 'SQL Query: ', <span>$sql</span><span>;   
</span><span>17</span>  <span>echo</span> 'Error: ' . <span>$e</span>-><span>getMessage();  
</span><span>18</span> <span>} 
</span><span>19</span> ?>

1. 使用 query()

<?<span>php
</span><span>$dbh</span>->query(<span>$sql</span>); 当<span>$sql</span> 中变量可以用<span>$dbh</span>->quote(<span>$params</span>); <span>//</span><span>转义字符串的数据</span>

<span>$sql</span> = 'Select * from city where CountryCode ='.<span>$dbh</span>->quote(<span>$country</span><span>);  
</span><span>foreach</span> (<span>$dbh</span>->query(<span>$sql</span>) <span>as</span> <span>$row</span><span>)   {    
 </span><span>print</span> <span>$row</span>['Name'] . "/t"<span>;    
 </span><span>print</span> <span>$row</span>['CountryCode'] . "/t"<span>;    
 </span><span>print</span> <span>$row</span>['Population'] . "/n"<span>; 
} 
</span>?>

2. 使用 prepare, bindParam和 execute [建议用,同时可以用添加、修改、删除]

<?<span>php
</span><span>$dbh</span>->prepare(<span>$sql</span><span>); 产生了个PDOStatement对象

PDOStatement</span>-><span>bindParam()

PDOStatement</span>->execute();<span>//</span><span>可以在这里放绑定的相应变量</span>
?>

3. 事物

<?<span>php 
 </span><span>try</span><span> {  
  </span><span>$dbh</span> = <span>new</span> PDO('mysql:host=localhost;dbname=test', 'root', ''<span>);  
  </span><span>$dbh</span>->query('set names utf8;'<span>);  
  </span><span>$dbh</span>->setAttribute(PDO::ATTR_ERRMODE, PDO::<span>ERRMODE_EXCEPTION);  
  </span><span>$dbh</span>-><span>beginTransaction();  
  </span><span>$dbh</span>-><span>exec</span>("Insert INTO `test`.`table` (`name` ,`age`)VALUES ('mick', 22);"<span>);  
  </span><span>$dbh</span>-><span>exec</span>("Insert INTO `test`.`table` (`name` ,`age`)VALUES ('lily', 29);"<span>); 
  </span><span>$dbh</span>-><span>exec</span>("Insert INTO `test`.`table` (`name` ,`age`)VALUES ('susan', 21);"<span>);  
  </span><span>$dbh</span>-><span>commit(); 
 } </span><span>catch</span> (<span>Exception</span> <span>$e</span><span>) {  
  </span><span>$dbh</span>-><span>rollBack();  
  </span><span>echo</span> "Failed: " . <span>$e</span>-><span>getMessage();  
 }  
</span>?> 

 

PDO常用方法：
PDO::query()主要用于有记录结果返回的操作（PDOStatement），特别是select操作。

PDO::exec()主要是针对没有结果集合返回的操作。如insert,update等操作。返回影响行数。
PDO::lastInsertId()返回上次插入操作最后一条ID，但要注意：如果用insert into tb(col1,col2) values(v1,v2),(v11,v22)..的方式一次插入多条记录，lastinsertid()返回的只是第一条(v1,v2)插入时的ID,而不是最后一条记录插入的记录ID。
PDOStatement::fetch()是用来获取一条记录。配合while来遍历。
PDOStatement::fetchAll()是获取所有记录集到一个中。
PDOStatement::fetchcolumn([int column_indexnum])用于直接访问列，参数column_indexnum是该列在行中的从0开始索引值，但是，这个方法一次只能取得同一行的一列，只要执行一次，就跳到下一行。因此，用于直接访问某一列时较好用，但要遍历多列就用不上。
PDOStatement::rowcount()适用于当用query("select ...")方法时，获取记录的条数。也可以用于预处理中。$stmt->rowcount();
PDOStatement::columncount()适用于当用query("select ...")方法时，获取记录的列数。

注解：
1、选fetch还是fetchall？
小记录集时，用fetchall效率高，减少从数据库检索次数，但对于大结果集，用fetchall则给系统带来很大负担。数据库要向WEB前端传输量太大反而效率低。
2、fetch()或fetchall()有几个参数：
mixed pdostatement::fetch([int fetch_style [,int cursor_orientation [,int cursor_offset]]])
array pdostatement::fetchAll(int fetch_style)

fetch_style参数:
■$row=$rs->fetchAll(PDO::FETCH_BOTH); FETCH_BOTH是默认的，可省，返回关联和索引。
■$row=$rs->fetchAll(PDO::FETCH_ASSOC); FETCH_ASSOC参数决定返回的只有关联数组。
■$row=$rs->fetchAll(PDO::FETCH_NUM); 返回索引数组
■$row=$rs->fetchAll(PDO::FETCH_OBJ); 如果fetch()则返回对象，如果是fetchall(),返回由对象组成的二维数组