Introduction
SQL injection is a type of attack in which an attacker inserts their own SQL commands into your website or application. This can happen when you pass user input to a database query without first validating it. You can use prepared statements and parameterized queries to prevent this from happening by guaranteeing that an attacker is not able to change the intent of a query, even if SQL commands are inserted by an attacker.
Prepared statements and parameterized queries force the developer to first define all the SQL code, and then pass in each parameter to the query later. This way the database knows in advance what to expect, and can refuse to run unexpected commands.
The following example shows how a query could be broken up into its SQL parts and parameters:
This can be done by assigning each part of the query a name, which is used to identify what part of the query should be executed. Then, each parameter in that part is assigned a value.
The result will look something like this:
<?php
$query = “SELECT * FROM table WHERE id=3 AND name=’Joe’;”;
$params = array();
$params[0] = ‘id’; // ID column
$params[1] = ‘name’; // Name column (first parameter)
$params[2]
Code: $stmt = $conn->prepare(‘SELECT * FROM users WHERE name = ?’);
This code is designed to select all of your users, and then filter out those who have a name that matches the supplied value. You can see that we are using prepared statements, which means that we create a statement object in advance and pass it into our query. Prepared statements make this process much more efficient than making an actual SELECT statement yourself (which would require you to write out all of those SQL keywords).
This code also uses parameterized queries, which means that instead of hard-coding values into each column name or value (and potentially causing errors), you can use placeholders for these values—or even just $1 through $10 placeholder variables—so that when someone enters something like “Bob” into one field, PHP knows what value should be returned from its server rather than returning nonsense data if someone types something else into another field!
$stmt->bind_param(‘s’, $name); // ‘s’ specifies the variable type => ‘string’
To bind a parameter to the SQL statement, use the bind_param method. The first argument is the name of your parameter (in this case it’s named s), and the second argument specifies its type: either string or integer.
For example:
$stmt->bind_param(‘s’, $name);
$stmt->execute();
$stmt->execute();
This method is a method of the PHP PDO statement class, and it’s used to execute a prepared statement. The return value from this method is true if the statement executed successfully, or false if there was an error during its execution.
In order to counter SQL injection attacks, prepared statements guarantee that an attacker is not able to change the intent of a query, even if SQL commands are inserted by an attacker. This is done by telling the database server to separate parts of an SQL statement from user input.
In order to counter SQL injection attacks, prepared statements guarantee that an attacker is not able to change the intent of a query, even if SQL commands are inserted by an attacker. This is done by telling the database server to separate parts of an SQL statement from user input.
Prepared statements allow developers to define all their queries in advance and then pass them into a function that will execute them on behalf of your application. The advantage here is that you have control over which parameters are sent by users when they make requests (e-commerce sites don’t want customers entering credit card numbers). This also prevents cross-site scripting attacks because there’s no way for users outside your site’s domain name space (such as www) to inject themselves into client-side code such as PHP scripts or HTML files!
Conclusion
In order to counter SQL injection attacks, prepared statements guarantee that an attacker is not able to change the intent of a query, even if SQL commands are inserted by an attacker. This is done by telling the database server to separate parts of an SQL statement from user input.
