mysqli_real_escape_string()函数是PHP中的内置函数, 用于本义所有特殊字符以用于SQL查问。在将字符串插入数据库之前应用它, 因为它删除了可能烦扰查问操作的任何特殊字符。

当应用简略的字符串时, 它们中可能蕴含特殊字符, 例如反斜杠和撇号(尤其是当它们间接从输出了此类数据的表单中获取数据时)。这些被认为是查问字符串的一部分, 并且会烦扰其失常运行。

<?php  $connection = mysqli_connect(     "localhost" , "root" , "" , "Persons" );          // Check connection if (mysqli_connect_errno()) {      echo "Database connection failed." ; }    $firstname = "Robert'O" ;$lastname = "O'Connell" ;   $sql ="INSERT INTO Persons (FirstName, LastName)              VALUES ( '$firstname' , '$lastname' )";      if (mysqli_query( $connection , $sql )) {           // Print the number of rows inserted in     // the table, if insertion is successful     printf( "%d row inserted.n" , $mysqli ->affected_rows);}else {           // Query fails because the apostrophe in      // the string interferes with the query     printf( "An error occurred!" );}   ?>

在下面的代码中, 查问失败, 因为应用mysqli_query()执行撇号时, 会将撇号视为查问的一部分。解决方案是在查问中应用字符串之前应用mysqli_real_escape_string()。

<?php   $connection = mysqli_connect(         "localhost" , "root" , "" , "Persons" );   // Check connection if (mysqli_connect_errno()) {      echo "Database connection failed." ; }        $firstname = "Robert'O" ;$lastname = "O'Connell" ;   // Remove the special characters from the// string using mysqli_real_escape_string   $lastname_escape = mysqli_real_escape_string(                     $connection , $lastname );                      $firstname_escape = mysqli_real_escape_string(                     $connection , $firstname );   $sql ="INSERT INTO Persons (FirstName, LastName)             VALUES ( '$firstname' , '$lastname' )";  if (mysqli_query( $connection , $sql )) {           // Print the number of rows inserted in     // the table, if insertion is successful     printf( "%d row inserted.n" , $mysqli ->affected_rows);}   ?>

输入如下：

1 row inserted.

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