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Surrogate Key & Slowly Changing Dimensions

Surrogate Key & Slowly Changing Dimensions. Surrogate Key. Solusi Surrogate Key. SQL Statement. CREATE TABLE negara ( negara_sk int IDENTITY(1,2) PRIMARY KEY, kode_negara varchar (10) NOT NULL, nama_negara varchar (50) NOT NULL, gdp int ) Identity( a,b ) : a : seed b : increment.

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Surrogate Key & Slowly Changing Dimensions

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  1. Surrogate Key & Slowly Changing Dimensions

  2. Surrogate Key

  3. Solusi Surrogate Key

  4. SQL Statement CREATE TABLE negara ( negara_skint IDENTITY(1,2) PRIMARY KEY, kode_negaravarchar(10) NOT NULL, nama_negaravarchar(50) NOT NULL, gdpint) • Identity(a,b) : • a : seed • b : increment

  5. INSERT negara (kode_negara, nama_negara, gdp) VALUES (‘IND’, ‘Indonesia’, 100) • INSERT negara (kode_negara, nama_negara, gdp) VALUES (‘SGP’, ‘Singapura’, 1000) • INSERT negara (kode_negara, nama_negara, gdp) VALUES (‘KAN’, ‘Kanada’, 1100)

  6. SELECT nama_negara, gdp FROM negara WHERE gdp > 100 SELECT negara.nama_negara, propinsi.nama_propinsiFROM negara, propinsi WHERE negara.kode_negara= ‘IND’ AND negara.negara_sk= propinsi.negara_sk

  7. Slowly changing dimensions

  8. SCD Type 1 : Correction of Errors • Contoh : • Perubahannama customer Michel Romano menjadi Michael Romano • Perubahannama customer setelahmenikah (Kristin Daniels menjadi Kristin Samuelson)

  9. SCD Type 2 : Preservation of History • Contoh : perubahan status customer menjadi married danperubahanalamat

  10. SCD Type 3 : Tentative Soft Revisions • Contoh : perubahanalamat customer

  11. Snowflake Schema

  12. Snowflake schema : normalisasitabeldimensipada Star Schema • Contoh : • Dimensi Product : • 50.000 products • 500 product brands • 10 product categories

  13. Aggregate fact table

  14. UkuranTabelFakta

  15. 300 stores, 500 products per brand Fact table  penjualan product per store per week • Query involves 1 product, 1 store, 1 week—retrieve/summarize only 1 fact table row • Query involves 1 product, all stores, 1 week—retrieve/summarize 300 fact table rows • Query involves 1 brand, 1 store, 1 week—retrieve/summarize 500 fact table rows • Query involves 1 brand, all stores, 1 year—retrieve/summarize 7,800,000 fact table rows

  16. Aggregates have fewer rows than the base tables • Formation of aggregate fact tables is certainly a very effective method to improve query performance

  17. One-Way Aggregates • Product category by store by date • Product department by store by date • All products by store by date • Territory by product by date • Region by product by date • All stores by product by date • Month by store by product • Quarter by store by product • Year by store by product

  18. Two-Way Aggregates • Product category by territory by date • Product category by region by date • Product category by all stores by date • Product category by month by store • Product category by quarter by store • Product category by year by store • Product department by territory by date • Product department by region by date • Product department by all stores by date • Product department by month by store • Product department by quarter by store • Product department by year by store • All products by territory by date • All products by region by date • All products by all stores by date • All products by month by store • All products by quarter by store • All products by year by store • District by month by product • District by quarter by product • District by year by product • Territory by month by product • Territory by quarter by product • Territory by year by product • Region by month by product • Region by quarter by product • Region by year by product • All stores by month by product • All stores by quarter by product • All stores by year by product

  19. Three-Way Aggregates • Product category by territory by month • Product department by territory by month • All products by territory by month • Product category by region by month • Product department by region by month • All products by region by month • Product category by all stores by month • Product department by all stores by month • Product category by territory by quarter • Product department by territory by quarter • All products by territory by quarter • Product category by region by quarter • Product department by region by quarter • All products by region by quarter • Product category by all stores by quarter • Product department by all stores by quarter • Product category by territory by year • Product department by territory by year • All products by territory by year • Product category by region by year • Product department by region by year • All products by region by year • Product category by all stores by year • Product department by all stores by year • All products by all stores by year

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