I'm using Entity Framework in my ASP.NET, C#, Web Application. If I need to select a record from DataBase (in Data Access Layer), which method should I use? Linq query or a Lambda Expression?
Eg:-
//Linq
var result = from a in db.myTable.Take(1) where a.Id == varId select a;
return result.First();
//Lambda
return db.myTable.FirstOrDefault(a => a.Id == varId);
Is there any preferred way in this scenario or any advantage over the other?
Linq query syntax is just a syntax sugar for expression methods. Any Linq query compiled into expression methods. Btw your first query:
var query = from a in db.myTable.Take(1)
where a.Id == varId
select a;
return query.First();
Is equivalent to
return db.myTable.Take(1).Where(a => a.Id == varId).First();
Both of your tries use Linq.
The first takes one record and checks if the id matches.
The second takes the first record where the id matches.
That's a difference.
Query Expression compiles into Method Expression (Lambda expression), so there shouldn't be any difference, In your code though you are accessing First
and FirstOrDefault
which would behave differently.
See: Query Syntax and Method Syntax in LINQ (C#)
and LINQ Query Expressions (C# Programming Guide)
At compile time, query expressions are converted to Standard Query Operator method calls according to the rules set forth in the C# specification. Any query that can be expressed by using query syntax can also be expressed by using method syntax. However, in most cases query syntax is more readable and concise.
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