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Detailed explanation of pdo error handling method in php

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2016-07-25 08:54:381038browse
  1. try {
  2. $db = new pdo('mysql:host=localhost;dbname=test', $user, $pass);
  3. $db = null;
  4. } catch (pdoexception $ e) {
  5.  print "error: " . $e->getmessage() . "
    ";
  6. die();
  7. }
  8. ?>
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Use php here 5. Object-oriented exception handling features. If there is an exception, call pdoexception to initialize an exception class.

Attribute structure of pdoexception exception class:

  1. class pdoexception extends exception
  2. {
  3. public $errorinfo = null; // Error message, you can call pdo::errorinfo() or pdostatement::errorinfo() to access
  4. protected $message ; // Exception information, you can use exception::getmessage() to access
  5.  protected $code; // SQL status error code, you can use exception::getcode() to access
  6. }
  7. ?>
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This exception handling class is integrated with the built-in exception handling class of PHP 5. PHP 5 built-in exception handling class structure:

  1. class exception
  2. {
  3.   // Property
  4. protected $message = 'unknown exception'; // Exception message
  5. protected $code = 0; // User-defined exception code
  6. protected $ file; // The file name where the exception occurred
  7. protected $line; // The code line number where the exception occurred
  8. // Method
  9. final function getmessage(); // Return exception information
  10. final function getcode(); // Return exception code
  11.  final function getfile(); // Returns the file name where the exception occurred
  12.  final function getline(); // Returns the code line number where the exception occurred
  13.  final function gettrace(); // backtrace() array
  14.  final function gettraceasstring() ; // The gettrace() information that has been formatted into a string
  15. }
  16. ?>
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Correspondingly, getfile() and getline() can be appropriately called in the code to locate the error. Make debugging easier. Use process-oriented approach Code:

  1. $db = new pdo('mysql:host=localhost;dbname=test', $user, $pass);
  2. $rs = $db->query("select aa, bb,cc from foo");
  3. if ($db->errorcode() != '00000'){
  4. print_r($db->errorinfo());
  5. exit;
  6. }
  7. $arr = $rs ->fetchall();
  8. print_r($arr);
  9. $db = null;
  10. ?>
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pdo and pdostatement objects have errorcode() and errorinfo() methods, if there are no errors , errorcode() returns: 00000, otherwise some error code will be returned. errorinfo() returns an array, including error codes defined by PHP and error codes and error messages of MySQL. The array structure is as follows: array ( [0] => 42s22 [1] => 1054 [2] => unknown column 'aaa' in 'field list' ) After each query is executed, the result of errorcode() is the latest, so we can easily control the error message display ourselves. What should I do if I encounter errors again during the development of PHP and database using pdo? Treat it as above.

11.3.4 Error handling of pdo

pdo provides two methods to obtain error information in the program, one is the errorcode() method; the other is the errorinfo() method.

1. errorcode() method

The

errorcode() method is used to obtain error codes that occur when operating database handles. These error codes are called sqlstate codes. The syntax format of this method is as follows:

01 string errorcode (void) The return value of the errorcode() method is a sqlstate. sqlstate is a code composed of 5 numbers and letters.

Example of using errorcode() method:

  1. $dsn = 'mysql:dbname=shop;host=localhost';
  2. $user_name = 'root';
  3. $user_psw = 'root';
  4. $pdo = new pdo($ dsn, $user_name, $user_psw);
  5. $pdo->exec("update mytable set age=28 where id=1 ");//The table mytable does not exist
  6. echo "errorcode is: ".$pdo-> errorcode();
  7. ?>
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The error code output is as shown below:

php pdo错误处理

2. errorinfo() method

The

errorinfo() method is used to obtain error information that occurs when operating a database handle. The syntax format of this method is as follows:

01 array errorinfo (void) The return value of the errorinfo() method is an array, which contains relevant error information.

Use errorinfo() method:

  1. $dsn = 'mysql:dbname=shop;host=localhost';
  2. $user_name = 'root';
  3. $user_psw = 'root';
  4. $pdo = new pdo($ dsn, $user_name, $user_psw);
  5. $pdo->exec("update mytable set age=28 where id=1 ");//The table mytable does not exist
  6. echo "errorinfo is: ";
  7. print_r($pdo ->errorinfo());
  8. ?>
Copy the error message output by the code

, as shown below: php pdo错误处理



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