Description: The entity mapper is a design pattern that maps data from one representation to another, facilitating interaction between different layers of an application, especially in the context of data persistence. This pattern is fundamental in software development as it allows for the decoupling of business logic from data access logic. By using an entity mapper, developers can transform domain objects into structures that can be stored in databases and vice versa, simplifying data management and improving code maintainability. The main features of the entity mapper include the ability to handle complex relationships between objects, automation of the data conversion process, and reduction of code duplication. This pattern is particularly relevant in applications that require constant interaction with databases, such as web applications, enterprise systems, and various types of software services. In summary, the entity mapper is a powerful tool that helps developers manage the complexity of modern applications by providing a structured way to handle data persistence.