What does “on-disk structure” means w.r.t Indexes in SQL Server – MSDN TSQL forum
According to MSDN, an index is an on-disk structure associated with a table or view that speeds retrieval of rows from the table or view.
In this definition, I don’t get what on-disk structure means.
–> My Answer:
Do not confuse with on-disk structure statement, not only index, a table is also an on-disk structure as all you data sits on-disk.
Check my response on you other similar question in MSDN TSQL forum.
Just like a table, an index is also on disk which can be built on top a table or separately.
– On top to restructure the whole table which is called the Clustered Index. Clustered Index is nothing but the table itself converted from a heap to a b-tree.
– Separately like a Non-Clustered index, which is a copy of the table with specific columns, created separately for performance reasons to read data will less columns.