linq to sql batch delete

Question

I have the following DB: Posts which have an Id, Tags also with Id, and TagsToPosts table which have T

Answer 1

Have you looked at the Linq Except operator?

For example:

var toDelete = (from t in TagsToPost
                select t).Except(from nt in newList
                                 select nt, new TagComparer());

class TagComparer: IEqualityComparer
{
    public bool Equals(TagsToPosts x, TagsToPosts y)
    {
         return x.Tag.Equals(y.Tag, CompareOptions.Ordinal);
    }
}