Suppose that I have a heap table with columns (id, name, gender, age)
If I have a NonClustered index in a column "name", what happens if I have like 10 people named "Lucas"? Does the index know which one "Lucas" he is point to? If there are so many Lucas' that they are separated in different pages on the B-Tree leafs, does the index still knowing how to find them and which row he has to point for every "Lucas"?
http://technet.microsoft.com/en-us/library/ms177484(v=sql.105).aspx