I know a HEAP is a table without a clustered index. But I'm not quite clear on the following definition from sys.indexes.
I understand that this system view contains row per index of a tabular object. But I get confused when I read, "contains a row per index or heap."
Why is the document using the word heap in the following definition, why per index or heap?
Contains a row per index or heap of a tabular object.
Ref: sys.indexes
A heap is a table without a clustered index. Because there is no ordering to the pages, it is a commonly accepted term to describe them. It can be confusing to people coming from other programming languages, where a heap refers to an entirely different type of entity.
Note that a table without a clustered index may have a nonclustered primary key, but the base object will still be a heap.
Adding a clustered index logically orders the table by the clustered index key(s).
