Please enable Javascript to correctly display the contents on Dot Net Tricks!

IEnumerable VS IQueryable

  Author : Shailendra Chauhan
Posted On : 16 Jun 2012
Total Views : 147,496   
Updated On : 28 Jan 2015
 

In LINQ to query data from database and collections, we use IEnumerable and IQueryable for data manipulation. IEnumerable is inherited by IQueryable, Hence IQueryable has all the features of IEnumerable and except this, it has its own features. Both have its own importance to query data and data manipulation. Let’s see both the fetures and take the advantage of both the fetures to boost your LINQ Query performance.

IEnumerable

  1. IEnumerable exists in System.Collections Namespace.

  2. IEnumerable can move forward only over a collection, it can’t move backward and between the items.

  3. IEnumerable is best to query data from in-memory collections like List, Array etc.

  4. While query data from database, IEnumerable execute select query on server side, load data in-memory on client side and then filter data.

  5. IEnumerable is suitable for LINQ to Object and LINQ to XML queries.

  6. IEnumerable supports deferred execution.

  7. IEnumerable doesn’t supports custom query.

  8. IEnumerable doesn’t support lazy loading. Hence not suitable for paging like scenarios.

  9. Extension methods supports by IEnumerable takes functional objects.

IEnumerable Example

 MyDataContext dc = new MyDataContext ();
IEnumerable<Employee> list = dc.Employees.Where(p => p.Name.StartsWith("S"));
list = list.Take<Employee>(10); 

Generated SQL statements of above query will be :

 SELECT [t0].[EmpID], [t0].[EmpName], [t0].[Salary] FROM [Employee] AS [t0]
WHERE [t0].[EmpName] LIKE @p0

Notice that in this query "top 10" is missing since IEnumerable filters records on client side

IQueryable

  1. IQueryable exists in System.Linq Namespace.

  2. IQueryable can move forward only over a collection, it can’t move backward and between the items.

  3. IQueryable is best to query data from out-memory (like remote database, service) collections.

  4. While query data from database, IQueryable execute select query on server side with all filters.

  5. IQueryable is suitable for LINQ to SQL queries.

  6. IQueryable supports deferred execution.

  7. IQueryable supports custom query using CreateQuery and Execute methods.

  8. IQueryable support lazy loading. Hence it is suitable for paging like scenarios.

  9. Extension methods supports by IQueryable takes expression objects means expression tree.

IQueryable Example

 MyDataContext dc = new MyDataContext ();
IQueryable<Employee> list = dc.Employees.Where(p => p.Name.StartsWith("S"));
list = list.Take<Employee>(10); 

Generated SQL statements of above query will be :

 SELECT TOP 10 [t0].[EmpID], [t0].[EmpName], [t0].[Salary] FROM [Employee] AS [t0]
WHERE [t0].[EmpName] LIKE @p0

Notice that in this query "top 10" is exist since IQueryable executes query in SQL server with all filters.

Summary

In this article I try to explain the difference between IEnumerable and IQueryable. I hope after reading this article you will be able to boost your LINQ query performance. I would like to have feedback from my blog readers. Please post your feedback, question, or comments about this article.



Free Interview Books
 
COMMENTS (0)
6 JUL
ASP.NET Core with Angular4 Development (Online)

7:00 AM-9:00AM IST(+5:30 GMT)T/T

Know More
5 JUL
NodeJS with Angular4 Development (Online)

08:00 PM-09:30 PM IST(+5.30 GMT)M/W/F

Know More
1 JUL
ASP.NET MVC with Angular4 Development (Online)

03:30 PM-05:30 PM IST(+5.30 GMT) Weekend

Know More
1 JUL
ASP.NET MVC with Angular4 Development (Classroom)

8:00 AM-10:00 AM Weekend

Know More
1 JUL
ASP.NET Core with Angular4 Development (Classroom)

3:00PM 5:00PM Weekend

Know More
1 JUL
Xamarin Forms : Build Cross-platform Apps (Classroom)

3:00 PM 5:00 PM Weekend

Know More
1 JUL
MEAN Stack 2 Development (Classroom)

11:00 AM-12:30 PM Weekend

Know More
30 JUN
ASP.NET MVC with Angular4 Development (Online)

07:00 AM-09:00 AM IST(+5.30 GMT) MON/WED/FRI

Know More
29 JUN
Hadoop Development cum Administration (Online)

7:00 AM-9:00AM IST(+5:30 GMT)T/W/T

Know More
26 JUN
Xamarin Forms : Build Cross-platform Apps (Online)

9:30PM- 11:00PM IST(+5:30GMT) M/W/F

Know More
26 JUN
Xamarin Forms : Build Cross-platform Apps (Online)

9:30PM- 11:00PM IST(+5:30GMT) M/W/F

6 JUN
ASP.NET MVC with Angular4 Development (Online)

09:00 PM-11:00 PM IST(+5.30 GMT)(TT)

3 JUN
ASP.NET MVC with Angular4 Development (Classroom)

4:00 PM-5:30 PM Weekend

20 MAY
Angular2 and Angular4 Development (Online)

08:00 AM-10:00 AM IST(+5.30 GMT) Weekend

20 MAY
NodeJS with Angular4 Development (Classroom)

5:30 PM-7:00 PM Weekend

8 MAY
ASP.NET MVC with Angular4 Development (Online)

07:00 AM-09:00 AM IST(+5:30 GMT) M/W/F

2 MAY
ASP.NET Core Development (Online)

07:00 AM - 09:00 AM IST( TUS, THR)

29 APR
ASP.NET MVC with Angular2 Development (Classroom)

9:30 AM-11:00 AM

BROWSE BY CATEGORY
 
 
LIKE US ON FACEBOOK
 
+