How to properly implement Unit Of Work?

Question

C++ / C#

Good day!
Tried to implement Unit Of Work and ran into a problem.
In the repository method
public IEnumerable GetAll()
{
return db.documents_proving_identity;
}
And when I do a search
from d in DocumentsProvingIdentityRepository.GetAll()
where array.ContainsKey(d.series)
select d
Then a complete selection comes from the database, without overlapping WHERE in (....)
How can I make sure that the query is generated correctly?

Answer 1

IEnumerable и IQueryable

Answer 2

То из базы идет полная выборка
GetAll