Entity Framework (EF) is an object-relational mapping (ORM) framework developed by Microsoft for .NET applications. It provides a set of tools and libraries that allow developers to work with relational databases using .NET objects, eliminating the need to write low-level data access code, SQL queries, and database schema manipulation manually. Entity Framework supports various database systems, including Microsoft SQL Server, MySQL, PostgreSQL, and SQLite.

In many programming languages, you can prevent a class from being inherited by using the sealed (C#) or final (Java) modifier. This modifier restricts the inheritance of a class, ensuring that no other class can extend or inherit from it. Here’s an example in both C# and Java:

In C#, there are several interfaces available for collections of data that can be iterated over or queried. These interfaces include IEnumerable, IEnumerator, IQueryable, ICollection, and IList. Each of these interfaces has its own unique characteristics and is used in different scenarios depending on the requirements of your application.