What is data encapsulation?

Data encapsulation refers to the concept in object-oriented programming where data (attributes) and methods (functions or procedures) that operate on the data are bundled together within a single unit, typically a class. This allows for a clear structure where the internal state of the object can be protected from outside interference and modification.

By encapsulating data, you ensure that the data can only be accessed or modified through defined methods, which promotes data integrity and security. This access control mechanism enables the implementation of abstraction and enhances maintainability, as the internal workings of a class can change without affecting other parts of the program that rely on it. This is fundamental to object-oriented programming as it aligns with principles like encapsulation, inheritance, and polymorphism.

The other options describe concepts that are not aligned with the precise understanding of data encapsulation. The separation of data and code is more related to structured programming principles, while removing data from systems does not pertain to encapsulation at all. Database joins involve connecting related records from different tables in a relational database, which is unrelated to the concept of encapsulating data and methods within classes.