On the way here on horseback - PDO connection error

Good things come hard, but there are some problems connecting to the database, which sometimes makes people angry.

1. Confirm that PDO is turned on

PDOmust be turned on in php 5.1 or above version under Windows environment.

Create a new test.php file in your own environment with the following content:

After running, you can see the picture below, which means it has been opened successfully. Go directly to 2.

If it cannot run, open the

php.iniconfiguration file and findextension=php_pdo.dll(configuration php configuration file, Turn on the corresponding extension) andextension=php_pdo_mysql.dll(turn on the extension to the corresponding database, take MySQL as an example), remove the previous ";" comment, and modify the two lines of configuration The content is as follows:

extension=php_pdo.dll extension=php_pdo_mysql.dll

After completion, restart

apache.

2. Database connection problem

1. Connect to

   MySQL

Note: If there are any connection errors, a

PDOExceptionexception object will be thrown.

b. Handling connection errors

query('SELECT * from student') as $row) { print_r($row); } $dbh = null;} catch (PDOException $e) { print "Error!: " . $e->getMessage() . "
"; die();} ?>

3. There are errors in the SQL statement itself

exec($sql); //错误判定：exec方法执行结果成功也存在返回0的情况，错误会返回false，所以要判定是否是SQL错误，需要判定结果为false if(false === $rows){ //取出错误细信息 echo 'SQL错误：
'; echo '错误代码为：' . $pdo->errorCode() . '
'; echo '错误原因为：' . $pdo->errorInfo()[2]; //errorInfo返回数组，2下标代表错误具体信息 exit; //错误不需要继续执行代码 } ?>

Statement problems can be solved by connecting to the

database, confirm the statement problem through thecmd command lineor database visualization software (such asNavicat, phpMyAdmin).

Recommended:

php tutorial,php video tutorial

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