Difference between Shallots, Bunching Onions & Chives

I'm confused. I just started my first vegetable garden, but I can not seem to get a straight answer on the difference between bunching onions and shallots. Do shallots just keep growing even after you pick them, or are they like bunching onions where once you pick one you have to plant another bulb in the same place to get another? Do shallots taste similar to bunching onions? I read a book that said otherwise. However, I went to a store (where I bought my shallot bulbs) and the person who helped me said "... French chefs use shallots in their cooking", while the book I read said that shallots are strong tasting and are usually just pickled.
Also, my father planted something that is now growing like a big patch similar to bunching onions, only it seems like they are all coming from the same bulb. He said that all he does is pick the green cylinder-type leaves and they keep growing... Those green cylinder-type leaves have a strong onion taste. What could this herb be... shallot or chive?
Please help!!! I would like to plant something that resembles a bunching onion, that is not too strong in taste, that I could put in salads and that I could pick from my vegetable garden and what I picked would then be replaced by the plant producing it. Does such a beast exist??

The plant you are looking for is probably Welsh onion (#S4310) which is a bulbless onion green that looks like a giant chive plant. As long as you only cut some its leaves but don't touch the root it will keep growing and eventually divide into multiple heads.
Shallots all look like bunching onions at the beginning of the growing season, but later on they will form multiple heads and the heads will all form a bulb in fall. This results in a cluster of bulblets that are harvested and stored like onions for over winter use.
There are many different types of shallots with slightly different bulb shapes, flavours and strengths of flavours. Dutch shallots taste like onions and can therefore be used as a substitute for bunching onions or chives during the early part of the season. But such use will reduce the number and size of the bulbs formed in the late summer. French shallots have a garlic-onion flavour and their bulbs have yellowish flesh. They could be used as a substitute for garlic chives or garlic during the early part of the growing season.