What is the use of IQueryable in the context of Linq.

Question

means How can use IQueryable and how it is better from IEnumerable?

Muralidharan Deenathayalan · Answer

The primary difference is that the extension methods defined for IQueryable take Expression objects instead of Functional objects meaning the delegate it receives is an expression tree instead of a method to invoke. IEnumerable is great for working with in-memory collections but IQueryable allows for a remote data source like a database or web service. IEnumerable doesn't have the concept of moving between items it is a forward only collection. It's very minimalistic; something that most any data source can provide. Using only this minimal functionality LINQ can provide all of these great operators. IQueryable is a very powerful feature that enables a variety of interesting deferred execution scenarios (like paging and composition based queries). Hope this helps !!! Source http://jonkruger.com/blog/2007/10/19/iqueryable-vs-ienumerable-in-linq-to-sql-queries/

Sandeep Shekhawat · Answer

Sorry Jagan sir i could not understand this. Please explain in general language as teaching sir not writing sir please.

Jaganathan Bantheswaran · Answer

Hi First of all IQueryable extends the IEnumerable interface so anything you can do with a plain IEnumerable  you can also do with an IQueryable . IEnumerable just has a GetEnumerator() method that returns an Enumerator for which you can call its MoveNext() method to iterate through a sequence of T. What IQueryable has that IEnumerable doesn't are two properties in particular—one that points to a query provider (e.g. a LINQ to SQL provider) and another one pointing to a query expression representing the IQueryable object as a runtime-traversable expression that can be understood by the given query provider (for the most part you can't give a LINQ to SQL expression to a LINQ to Entities provider without an exception being thrown). The expression can simply be a constant expression of the object itself or a more complex tree of a composed set of query operators and operands. The query provider's IQueryProvider.Execute() or IQueryProvider.CreateQuery() methods are called with an Expression passed to it and then either a query result or another IQueryable is returned respectively. Source: Link