LINQ Interview QuestionsWhat is LINQ?Explain the main benefits of LINQWhat are the different types of LINQ?What is the difference between LINQ to Objects and LINQ to SQL?What are different methods to write LINQ Query in C#?Explain the concept of deferred loading in LINQ to SQL.What is eager loading in LINQ?What is lazy loading in LINQ?Can you disable lazy/deferred loading?What is explicit loading in LINQ?What is IQueryable in LINQ?What is the difference between IQueryable and IEnumerable?What are lambda expressions in LINQ?What is Can we use ref and out paramters in lambda expression? if declared outside?What is LINQ provider and explain different types of LINQ providers?What are advantages of LINQ over DataSet?What is the difference between LINQ and stored procedures?What are the disadvantages of LINQ over stored procedure?Difference between ADO.Net and LINQ to SQL?How can you handle concurrency in LINQ to SQL?How can you handle concurrency at field level in LINQ to SQL?What is the purpose of "Any" operator in LINQ?What is the purpose of "All" operator in LINQ?What is the difference between "Any" and "All" operators in LINQ?What is the purpose of "Contains" operator in LINQ?What is the difference between "Any" and "Contains" operators in LINQ?What is the purpose of "Count" operator in LINQ?What is the purpose of "Min" operator in LINQ?What is the purpose of "Max" operator in LINQ?What is the purpose of "Sum" operator in LINQ?What is the purpose of "Average" operator in LINQ?What is the purpose of "ToList" operator in LINQ?What is the purpose of "ToArray" operator in LINQ?What is the difference between "ToList" and "ToArray" methods in LINQ?What is the purpose of "ToDictionary" operator in LINQ?What is the purpose of "ToLookup" operator in LINQ?What is the purpose of "Cast" operator in LINQ?What is the purpose of "First" operator in LINQ?What is the purpose of "FirstOrDefault" operator in LINQ?What is the difference between First and FirstOrDefault in LINQ?What is the purpose of "Single" operator in LINQ?What is the purpose of "SingleOrDefault" operator in LINQ?What is the difference between "Single" and "SingleOrDefault" in LINQ?What is the purpose of "Last" operator in LINQ?What is the purpose of "LastOrDefault" operator in LINQ?What is the difference between "Last" and "LastOrDefault" in LINQ?What is the purpose of "Where" operator in LINQ?What is the use of "Select" operator in LINQ?When to use "SelectMany" operator in LINQ?What is the difference between "Select" and "SelectMany" in LINQ?What is the purpose of "OrderBy" clause in LINQ?What is the purpose of "GroupBy" clause in LINQ?What is the usage of "Having" clause in LINQ?What is the purpose of "Distinct" method in LINQ?How do you use the "Distinct" method with a custom equality comparer in LINQ?What is the purpose of "Concat" method in LINQ?What is the purpose of "Skip" method in LINQ?What is the purpose of "Take" method in LINQ?
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Difference between IQueryable and IEnumerable

IQueryable and IEnumerable are both interfaces in LINQ that provide a way to work with collections and perform queries. However, they have some key differences in terms of their functionality and intended usage:

  1. Execution Model:
    • IEnumerable is designed for querying in-memory collections and represents a sequence of objects. The query operations are executed in-memory using LINQ-to-Objects.
    • IQueryable is designed for querying external data sources (e.g., databases) and represents a query that can be translated and executed on the data source. The query operations are executed remotely using a provider-specific query language (e.g., SQL for a database).
  2. Deferred Execution:
    • IEnumerable supports deferred execution, which means the query is not executed until the data is enumerated. Each query operation is applied one at a time as the elements are accessed in a foreach loop or when methods like ToList() or ToArray() are called.
    • IQueryable also supports deferred execution, but it allows for more advanced query composition. The query is represented as an expression tree, and additional query operations can be chained together before execution. The entire expression tree is translated and executed at once on the remote data source.
  3. Query Translation:
    • IEnumerable works with LINQ-to-Objects and operates on in-memory data. The query operators are executed using methods implemented by the collection or object being queried.
    • IQueryable works with LINQ providers that can translate the query into a specific query language (e.g., SQL) understood by the data source. The expression tree representing the query is analyzed and converted into an appropriate query for execution on the remote data source.
  4. Flexibility:
    • IEnumerable provides a simpler and more general-purpose interface for working with collections. It is suitable for scenarios where the data is already in memory or when the query operations are basic and don't require provider-specific features.
    • IQueryable provides additional capabilities for working with external data sources and leveraging their specific features. It allows for more complex query composition, provider-specific optimizations, and efficient execution on the data source.

In summary, IEnumerable is suitable for in-memory collections and simple querying, while IQueryable is designed for querying remote data sources and allows for more advanced query composition and execution optimization.

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