IQueryable vs. IEnumerable

1. iqueryable<t> extends the ienumerable<t> interface
2. ienumerable<t> is great for working with sequences that are iterated in-memory, but
3. iqueryable<t> allows for out-of-memory things like a remote data source, such as a database or web service
4. ienumerable<t>: loads all data into memory then filter. iqueryable<t>: filter data then loads the data into memory
5. links: