Which is better IQueryable or IEnumerable?

While querying data from database, IEnumerable executes select query on server side, load data in-memory on client side and then filter data. Hence does more work and becomes slow. While querying data from database, IQueryable executes select query on server side with all filters. Hence does less work and becomes fast.

Should I return IQueryable?

Returning IQueryable will definitely afford more flexibility to the consumers of the repository. It puts the responsibility of narrowing results off to the client, which naturally can both be a benefit and a crutch.

How IEnumerable interface differs from IQueryable?

Querying data from a database, IEnumerable execute a select query on the server side, load data in-memory on a client-side and then filter data. Querying data from a database, IQueryable execute the select query on the server side with all filters.

Is IQueryable faster than list?

GetList(context) might return an object backed by a custom LINQ provider (like an Entity Framework collection), then you probably want to leave the data cast as an IQueryable: even though your benchmark shows it being 20 times faster to use a list, that difference is so small that no user is ever going to be able to …

Which is better IEnumerable or list?

In terms of performance, the answer is it depends. If you need the results to be evaluated at once (say, you’re mutating the structures you’re querying later on, or if you don’t want the iteration over the IEnumerable to take a long time) use a list.

What is the repository pattern?

The Repository pattern is a well-documented way of working with a data source. A repository performs the tasks of an intermediary between the domain model layers and data mapping, acting in a similar way to a set of domain objects in memory.

What is an IQueryable in C#?

The IQueryable interface is intended for implementation by query providers. The IQueryable interface inherits the IEnumerable interface so that if it represents a query, the results of that query can be enumerated. Enumeration causes the expression tree associated with an IQueryable object to be executed.

What’s the difference between IQueryable and IEnumerable?

IEnumerable exists in System.Collections Namespace.

When to use IEnumerable?

IEnumerable interface is commonly used when dealing with collections and reading a collection’s items. Many times there is a need to loop through a collection of classes or lists which are anonymous types.

What does IEnumerable mean?

IEnumerable. IEnumerable is a standard interface that enables iterating over collections that supports it (in fact, all collection types I can think of today implements IEnumerable ). Compiler support allows language features like foreach. In general terms, it enables this implicit iterator implementation.

Does array implement IEnumerable?

Arrays do implement IEnumerable , but it is done as part of the special knowledge the CLI has for arrays. This works as if it were an explicit implementation (but isn’t: it is done at runtime). Many tools will not show this implementation, this is described in the Remarks section of the Array class overview.