Here is my storage for Artists
        
        1 -> a record
        2 -> a record
        ...
        49 -> a record
        
        on disk Oracle has 2 files
        1) the index (small file) holding the keys and the pointer (disk offset)
            to the record
        2) the records (large file) w/ all the data
        
        when I query using the primary key, oracle does 2 disk lookups
        1) search the Index, binary search
        2) using the disk offset, do a direct read of the record
        
        If I do not have an index (where city = 'Boston') Oracle MUST do
        a FULL TABLE SCAN and this is slow
        
        As an Appl Support DBA, the more I know how the data is used
        the more I will build "extra" indexes
        
        the cost of adding an index to a column is...
        an extra file on disk, the cost to insert/update/delete goes up
        becuase Oracle must change 2 files (index/data)
        
        however the cost to query goes down
        
        ------------------------------------------
        
        a Data Warehouse has a Second Database on top of the orginal DB
        this secnd DB is the indexes to the orginal