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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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