What are the potential drawbacks of storing multiple usernames in a single database column separated by commas in PHP?

Storing multiple usernames in a single database column separated by commas can make it difficult to query and manipulate the data efficiently. It violates the principles of database normalization and can lead to issues such as data redundancy, difficulty in searching for specific usernames, and potential data inconsistency. To solve this issue, it is recommended to create a separate table to store the usernames in a normalized way, with each username in its own row. 

// Create a separate table to store usernames in a normalized way
CREATE TABLE user_names (
    id INT AUTO_INCREMENT PRIMARY KEY,
    username VARCHAR(50)
);

// Insert usernames into the new table
INSERT INTO user_names (username) VALUES ('username1'), ('username2'), ('username3');

// Retrieve usernames from the new table
SELECT username FROM user_names;

Keywords

PHP database normalization explode performance

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