Indexes of SQL Server are SIMILAR to the indexes in books. They help SQL Server retrieve the data quicker. Indexes are of two types. Clustered indexes and non-clustered indexes. Rows in the table are stored in the order of the clustered index KEY.
There can be only ONE clustered index PER table.
Non-clustered indexes have their own storage separate from the table data storage.
Non-clustered indexes are stored as B-tree structures.
Leaf level nodes having the index key and it's ROW locater.

Indexes of SQL Server are similar to the indexes in books. They help SQL Server retrieve the data quicker. Indexes are of two types. Clustered indexes and non-clustered indexes. Rows in the table are stored in the order of the clustered index key.
There can be only one clustered index per table.
Non-clustered indexes have their own storage separate from the table data storage.
Non-clustered indexes are stored as B-tree structures.
Leaf level nodes having the index key and it's row locater.