Entity Framework - Performance in count

Question

I\'ve a little question about performance with Entity Framework.

Something like

using (MyContext context = new MyContext())
{
    Document DocObject         


        

Answer 1

Because ToList() will query the database for the whole objects (will do a SELECT * so to say), and then you'll use Count() on the list in memory with all the records, whereas if you use Count() on the IQueryable (and not on the List), EF will translate it to a simple SELECT COUNT(*) SQL query