I'm using .NET Core with EF and I've got to perform join operation on 2 tables from different databases, so I can't use just IQueryable.
I'm wondering which collection type will be the best when it's obligatory to upload all the values from DB to local memory and the amount of data of the both tables is quite big, and later we want to LINQ join both tables?
I don't want to update/delete any values later.
In my opinion, the best would be a HashSet or maybe even better Dictionary?
But what's your opinion and why? Thanks!