Solving the Duplicate Email, Username, and Number Error in PHP

Learn how to fix the `mysqli_query()` error while ensuring unique entries for email, username, and mobile in your PHP registration system.
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Solving the Duplicate Email, Username, and Number Error in PHP

In the arena of web development, creating a user registration system that prevents duplicate entries is crucial for maintaining data integrity. However, you might encounter errors that prevent your code from functioning as expected. One particular issue arises when trying to check for duplicate email addresses, usernames, or mobile numbers in a PHP application.

In this guide, we will discuss the common errors encountered and provide you with a thorough breakdown of how to resolve them in your registration system.

The Problem at Hand

If you're using the provided PHP code for user registration and face the following error:

[[See Video to Reveal this Text or Code Snippet]]

This error usually indicates a failure in the database connection that stops the mysqli_query() from executing properly. The potential issues could stem from the connection to the database or mistakes in your query logic.

The Root Cause

The error message gives us a hint that there's an issue with the arguments passed to the mysqli_query() function. Specifically, it suggests that the first argument, which should be a valid mysqli object, is returning false. This typically happens when the database connection has failed, which often involves running queries against a non-existent database or port number.

Solution Breakdown

Let's take a step back and review the critical parts of your code, particularly in the section where you check for duplicate entries, and we'll include necessary corrections.

1. Verify Database Connection

First and foremost, confirm that your database connection is correctly established. Ensure your connection.php file is error-free and properly connects to the database. For example:

[[See Video to Reveal this Text or Code Snippet]]

2. Review Duplicate Checking Logic

You might encounter errors while comparing the values retrieved from the database. Below is the corrected version of the checks:

[[See Video to Reveal this Text or Code Snippet]]

3. Key Adjustments

Ensure the correct comparison in conditions: The original code used mysqli_num_rows($uq > 0), which should be mysqli_num_rows($uq) > 0.

Error Handling: We also added a way to handle errors encountered during the insert query.

Conclusion

By following the steps outlined in this post, you can resolve the mysqli_query() error and implement an effective check against duplicate usernames, emails, and mobile numbers in your PHP registration system.

Make sure to carefully verify your database connection and query syntax to prevent these issues in the future. Happy coding!

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