Could you describe the concept of levels in the data validation process?

The concept of levels in the data validation process involves dividing data checks into several stages or levels, each responsible for a specific type of validation. This helps structure the validation process, making it more manageable and understandable.

For example, the following levels can be distinguished:

1. Syntactic level — checking the data format (e.g., whether a string matches the email format, correctness of data type).
2. Semantic level — checking the logic and meaning of data (e.g., a birth date cannot be in the future).
3. Business level — checking rules specific to business logic (e.g., a user must be over 18 years old to register).

This approach allows early filtering of simple errors and gradually moving to more complex checks, improving the quality and reliability of data processing.