Can you name common deviations or problems encountered in databases?

The typical problems and deviations in a database include:

• Data integrity violations: such as missing foreign keys or incorrect relationships between tables.
• Data duplication: due to lack of normalization or insertion errors.
• Performance issues: slow queries caused by missing indexes or inefficient queries.
• Locks and deadlocks: when transactions conflict, causing hangs.
• Data loss during failures: due to lack of backups or improper transaction settings.
• Incorrect data types usage: leading to errors or excessive memory usage.

For example, if a users table lacks a unique constraint on email, duplicates may appear, causing authentication problems.