How to Fix 'Deprecated mysql_* Functions' Errors After Upgrading PHP?

Error Handling After PHP Upgrade: Outdated mysql_* Functions

As you've discovered upon upgrading from PHP 5.2 to 5.5, several of your PHP code snippets are encountering errors related to deprecated or outdated mysql_* functions. Let's explore these issues and provide solutions.

Deprecated mysql_real_escape_string() Function

The mysql_real_escape_string() function is used to protect against SQL injection attacks. However, it has been deprecated in newer versions of PHP in favor of a more secure alternative.

Solution: Replace mysql_real_escape_string() with mysqli_real_escape_string() to ensure continued reliability.

Incorrect Number of Arguments for mysqli_real_escape_string()

The mysqli_real_escape_string() function requires two arguments: the connection resource and the string to be escaped. In your example, you are only providing one argument.

Solution: Establish a connection to the database and pass the connection resource to mysqli_real_escape_string() as the first argument. The syntax for establishing a connection looks like this:

<code class="php">$connection = mysqli_connect("host", "my_user", "my_password", "my_db");</code>

Alternative Option: Database Objects

Instead of manually passing in the connection resource each time, you can use a database object to simplify the process. This approach involves setting up a database object as follows:

<code class="php">$mysqli = new mysqli("host", "my_user", "my_password", "my_db");</code>

Once you have created the database object, you can use its built-in functions to perform database operations without explicitly passing in the connection resource. For example:

<code class="php">$result = $mysqli->query("SELECT * FROM login WHERE username = '{$username}' AND password = '{$password}' AND status=1");</code>

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