Entity Framework : better way to do many to many query? - asp.net-mvc

Question

Environment: EF6 code first
I have two tables e.g user and activity which have a many-to-many relation.
I want to know whether any user's activity has a given key, using Entity Framework in an asp.net mvc application.
is the following query performance wise?
is there any other way to write this query?
Query:
var userEntity = _dbcontext.Users.Find(userId);
var isAvailable = _dbcontext.Entry(userEntity)
.Collection(e => e.Activities)
.Query().Any(e => e.Name== "givenname");
updated:
i ran those queries and here are the time to run:
1
var userEntity = _dbcontext.Users.Find(userId);
var isAvailable = userEntity.Activities.Any(a => a.Name == "givenname");
time: 5.39s + time to fetch user
2
var isAvailable =_dbcontext.Users.Include(e => e.Activities)
.Any( u => u.UserId == userId
&& u.Activities.Any(a => a.Name == "givenname")
);
time: 5.73s
3
var userEntity = _dbcontext.Users.Find(userId);
var isAvailable = _dbcontext.Entry(userEntity)
.Collection(e => e.Activities)
.Query().Any(e => e.Name== "givenname");
time: 5.95s + time to fetch user
so it seems that choosing the second form of query be reasonable.

Answer 1

You can also try this:
var isAvailable =_dbcontext.Users.Include(e => e.Activities)
.Any( u => u.UserId == userId
&& u.Activities.Any(a => a.Name == "givenname")
);
If you haven't disabled lazy loading, then you don't need to call the Include extension method.

Answer 2

I would simplify this to:
var userEntity = _dbcontext.Users.Find(userId);
var isAvailable = userEntity.Activities.Any(a => a.Name == "givenname");
or maybe (I'm not quite clear what you're trying to achieve, from your question) - this doesn't take the userId into account, it just searches for any users that has any activity with that givenname:
var isAvailable = _dbcontext.Users.Any(u => u.Activities.Any(a => a.Name == "givenname"));

Answer 3

Single trip to the DB:
var result = _dbcontext.Users.Where( u => u.UserId == userId )
.Select( u => new {
User = u, // optional
IsAvailable = u.Activities.Any( a => a.Name == "givenname" )
} )
.SingleOrDefault();