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Data Warehousing & Business Intelligence2025

Casestudy 07

SQL Data Warehouse & BI Analytics

Enterprise Medallion Warehouse & BI Star Schema

SQL ServerPostgreSQLKimball Star SchemaSCD Type 2T-SQL

The Vision & Architecture

Reconciling ERP & CRM data silos into a single, high-performance Star Schema.

End-to-end data warehouse engineering project integrating siloed CRM and ERP source systems into an optimized Kimball dimensional star schema. Implements Medallion staging, automated data quality cleansing, SCD Type 2 dimension historization, and complex analytical CTE reporting.

2 SilosCRM & ERP Unified
100%Duplicate Removal
Star SchemaGold Reporting Layer
SCD Type 2Dimension Historization

Core Capabilities

  • Master Data Integration (CRM + ERP)

    Reconciled disparate customer demographics, product catalogs, and transaction records across siloed enterprise business systems.

  • Data Quality & Cleansing Automation

    Resolved duplicate customer records, out-of-bounds dates, compound SKU key prefixes, and formatting inconsistencies using advanced T-SQL.

  • Kimball Dimensional Modeling

    Constructed a high-performance Gold Star Schema with central fact tables and denormalized dimension tables for rapid BI aggregation.

  • SCD Type 2 Analytical Historization

    Dynamically generated dimension validity windows (start_date, end_date) using SQL window functions (LEAD/LAG) to track attribute drift.

  • Advanced BI Reporting Queries

    Authored multi-CTE queries calculating Customer Lifetime Value (CLV), RFM customer segmentation cohorts, and product margin analyses.

Technology Stack

Transact-SQL / PostgreSQLRelational Warehouse Core
Kimball ModelingStar Schema & Dimensions
Medallion ArchitectureBronze, Silver, Gold
Advanced CTEsAnalytical BI Marts
BULK INSERT EngineHigh-Throughput Ingestion

Architectural Decisions

  • Star schema over normalized 3NF for reporting marts

    Denormalized dimensions eliminate complex multi-table joins and significantly accelerate analytical dashboard queries.

  • Database-generated surrogate keys

    Surrogate keys decouple the warehouse from source ERP/CRM identifier changes, ensuring durable analytical integrity.