【正文】
28 Inspur group ? 有沒有帶緩慢變化維度一致性維度 ? 有沒有跨層取數(shù)的現(xiàn)象 25 ETL 34個子系統(tǒng) 抽取 在 ETL環(huán)境中從源系統(tǒng)收集原始數(shù)據(jù)并且在任何對數(shù)據(jù)的重要重構(gòu)發(fā)生之前都將數(shù)據(jù)寫入磁盤。 14 星形模型缺點 2023/3/28 Inspur group Benefits: Simpler queries Simplified business reporting logic Query performance gains Expansibility Disadvantages redundancy data Harder Complex Queries 15 緩慢變化維 2023/3/28 Inspur group Supplier_Key Supplier_Code Supplier_Name Supplier_State 123 ABC Acme Supply Co CA Supplier_Key Supplier_Code Supplier_Name Supplier_State 123 ABC Acme Supply Co IL original Now 16 緩慢變化 維處理方式 2023/3/28 Inspur group Type 0: retain original Type 1: overwrite Type 2: add new row Type 3: add new attribute Type 4: add history table Type 6: hybrid 17 Type 2 TYPE 3 2023/3/28 Inspur group Supplier_Key Supplier_Code Supplier_Name Supplier_State Start_Date End_Date 123 ABC Acme Supply Co CA 01Jan2023 21Dec2023 124 ABC Acme Supply Co IL 22Dec2023 NULL Supplier_Key Supplier_Code Supplier_Name Original_Supplier_State Effective_Date Current_Supplier_State 123 ABC Acme Supply Co CA 22Dec2023 IL 18 Type 4: add history table 2023/3/28 Inspur group Supplier_key Supplier_Code Supplier_Name Supplier_State 124 ABC Acme Johnson Supply Co IL Supplier_key Sup