Building the Data Warehouse

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•    very compact


•    some loss of detail


•the older data gets, the less detail is kept


simple cumulative data


О




Jan 1


Jan 2


Jan 3 . . .


•    much storage required


•    no loss of detail


О




• much processing to do anything


Feb 1


Feb 2


Feb 3 . . .


with data


О




Mar 1


Mar 2


Mar 3 . . .

Figure 2.22 Comparing simple cumulative data with rolling summary data.


J


Adams


Jan-pres


123 Main Street


W


Abraham


Feb-pres


12 Hwy 9


P


Anderson


Jan-Jan


456 High Street


P


Anderson


Feb-pres


1455 Tincup Ct


K


Appleby


Jan-pres


10 A Street


L


Azimoff


Jan-pres


64 N Ranch Rd

Figure 2.23 Creating a continuous file from direct files.



January Customers



J Adams    123 Main Street


P Anderson    456 High Street


K Appleby    10 A Street


L Azimoff    64 N Ranch Rd



January Customers



February customers



J Adams    123 Main Street


P Anderson    456 High Street


K Appleby    10 A Street


L Azimoff    64 N Ranch Rd



J


Adams


123 Main Street

Скачать в pdf «Building the Data Warehouse»