Three data marts, three truths about sales: the bus matrix as common ground
Kimball bus matrix to align isolated data marts: conformed dimensions, business processes and comparable sales. Real insurance group case.
Dimensional-Modeling
5 tagged articles
Data Warehouse
Data Warehouse
DWH Partitioning: When 3 Years of Data Weigh Too Much
Range partitioning on an 800-million-row fact table: from 12-minute quarterly queries to 40 seconds. Monthly implementation, exchange and local indexes.
Data Warehouse
Ragged hierarchies: when the client has no parent and the group has no grandparent
Ragged hierarchy in the data warehouse: balancing unbalanced trees with the self-parenting technique. Correct drill-down on customers and groups.
Data Warehouse
SCD Type 2: the history the business didn't know it needed
SCD Type 2 in the data warehouse: historicising dimensions with surrogate keys and validity dates. Real case: a customer dimension that evolves over time.
Data Warehouse
Wrong grain: when the fact table can't answer the right questions
Data warehouse: fact table grain determines which questions you can answer. Common mistakes in granularity and their impact on the dimensional model.