How to Prepare a Statement for an Update Query

To enhance data security when updating a database using a PHP MySQLi query, it's recommended to employ a prepared statement. While the PHP documentation provides information on bind_param(), it lacks examples specific to update queries.

Let's delve into how to formulate a prepared statement for an update query:

1. Prepare the Query Statement:
   Replace all variables in the update query with question marks:

   $sql = "UPDATE Applicant SET phone_number=?, street_name=?, city=?, county=?, zip_code=?, day_date=?, month_date=?, year_date=? WHERE account_id=?";

2. Create and Prepare the Statement:

   • Create a statement object: $stmt = $db_usag->prepare($sql);
   • Prepare the statement using the query string.

3. Bind Parameters:

   • Specify the data types of the parameters (e.g., strings, integers).
   • Bind the variables to the question marks: $stmt->bind_param('sssssdddd', $phone_number, $street_name, $city, $county, $zip_code, $day_date, $month_date, $year_date, $account_id);.

4. Execute the Statement:

   • Execute the prepared statement: $stmt->execute();

5. Handle Errors:

   • Check for execution errors and print an error message if necessary: if ($stmt->error) { echo "FAILURE!!! " . $stmt->error; }

6. Close the Statement:

   • Close the statement object: $stmt->close();

7. Retrieve Result Information:

   • If the query is successful, you can retrieve information about the affected rows using: $stmt->affected_rows

By following these steps, you can effectively prepare a statement for an update query, ensuring data integrity and preventing potential security vulnerabilities.