Dw design 2_conceptual_model

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Modelo Conceptual

Modelo Conceptual

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  • 1. DATA WAREHOUSINGMulti DimensionalData ModelingConceptual Modeling
  • 2. 2
  • 3.  Modeling data warehouses: dimensions & measures  Star schema  Snowflake schema  Fact constellations3 3
  • 4. product prodId name price store storeId city p1 bolt 10 c1 nyc p2 nut 5 c2 sfo c3 la sale oderId date custId prodId storeId qty amt o100 1/7/97 53 p1 c1 1 12 o102 2/7/97 53 p2 c1 2 11 105 3/8/97 111 p1 c3 5 50 customer custId name address city 53 joe 10 main sfo 81 fred 12 main sfo 111 sally 80 willow la4 4
  • 5.  Modeling data warehouses: dimensions & measures  Star schema: A fact table in the middle connected to a set of dimension tables5 5
  • 6.  Modeling data warehouses: dimensions & measures  Snowflake schema: A refinement of star schema where some dimensional hierarchy is normalized into a set of smaller dimension tables, forming a shape similar to snowflake store city region6 6
  • 7. store city region sType tId size location t1 small downtownstore storeId cityId tId mgr t2 large suburbs s5 sfo t1 joe s7 sfo t2 fred city cityId pop regId s9 la t1 nancy sfo 1M north la 5M south region regId name north cold region south warm region 7
  • 8.  Connects entities to dimension tables rather than the fact table Complicates coding and requires additional processing for retrievals Useful for seldom used lookups 8
  • 9. timetime_key itemday item_key supplierday_of_the_week Sales Fact Table item_name supplier_keymonth brand supplier_typequarter time_key typeyear item_key supplier_key branch_key branch location location_key location_key branch_key units_sold street branch_name city_key branch_type dollars_sold city city_key avg_sales city state_or_province Measures country 9 9
  • 10.  Modeling data warehouses: dimensions & measures  Fact constellations: Multiple fact tables share dimension tables, viewed as a collection of stars, therefore called galaxy schema or fact constellation10 10
  • 11. timetime_key item Shipping Fact Tableday item_keyday_of_the_week Sales Fact Table item_name time_keymonth brandquarter time_key type item_keyyear supplier_type shipper_key item_key branch_key from_location branch location_key location to_locationbranch_key location_key dollars_costbranch_name units_sold streetbranch_type dollars_sold city units_shipped province_or_state avg_sales country shipper Measures shipper_key shipper_name location_key 11 shipper_type 11 11
  • 12.  The Data Warehouse Toolkit.Second Edition.The Complete Guide to Dimensional Modeling.Ralph Kimball.Margy Ross