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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What is IQueryable in LINQ?

IQueryable is a fundamental concept in LINQ (Language Integrated Query), and it's used to query data from various data sources like databases, collections, or other data providers in a way that allows you to build queries dynamically and efficiently retrieve data. The 'IQueryable' interface is derived from the IEnumerable interface, which means it inherits all the query operators defined in IEnumerable as well.

Imagine you have a large dataset, like a database table with millions of records. If you were to fetch all of this data into memory and then filter it, it would consume a lot of resources and could be slow. IQueryable solves this problem by allowing you to create a query expression without actually executing it immediately. Instead, it keeps track of the query expression and only fetches the data when necessary.

Here's a simple analogy: Think of IQueryable as creating a shopping list without actually buying the items. You can add, remove, or modify items on your list (build your query) without going to the store (executing the query) until you're ready to check out (retrieve the data).

This delayed execution is especially helpful when dealing with large datasets or remote data sources like databases, as it enables you to optimize and fine-tune your query before it's executed.

Here's an example of using IQueryable: 


// Assuming a data context named "context" and a table named "Customers"
IQueryable query = context.Customers.Where(c => c.Age > 25).OrderBy(c => c.LastName);

// The query is not executed here; it's just a representation of the query
// You can continue composing the query by adding more operators

// To execute the query and retrieve the results, you can enumerate over the query
foreach (Customer customer in query)
{
    Console.WriteLine(customer.Name);
}

In the example above, the Where and OrderBy operators are applied to the IQueryable object to filter and order the data. The query is not executed until the foreach loop, which triggers the execution and retrieves the results from the data source.

Using IQueryable allows for more efficient and optimized query execution by leveraging the capabilities of the underlying data source.

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