Data Warehouse
A centralized, historical data repository optimized for query, reporting and business intelligence.
Classification
- ComplexityHigh
- Impact areaTechnical
- Decision typeArchitectural
- Organizational maturityIntermediate
Technical context
Principles & goals
Use cases & scenarios
Compromises
- Outdated data models lead to wrong decisions
- Lack of governance causes inconsistencies
- Cost explosion from uncontrolled data growth
- Start with clear, limited domains and extend iteratively
- Automated tests and CI for data pipelines
- Document semantics, lineage and responsibilities
I/O & resources
- Source systems: ERP, CRM, IoT, logs
- Master data and reference lists
- Business requirements and KPI definitions
- Consistent data marts and semantic layers
- Reports, dashboards and analytical datasets
- Auditable lineage and archiving
Description
A data warehouse is a centralized, structured repository of historical and integrated enterprise data optimized for query and analysis. It consolidates heterogeneous sources, standardizes schemas and supports business intelligence, reporting and analytical workloads. Common elements include ETL/ELT pipelines, dimensional models and governance.
✔Benefits
- Consistent, enterprise-wide KPI baseline
- Historization and reproducibility of analyses
- Efficient aggregation and complex queries
✖Limitations
- High implementation and operational effort
- Latency between events and available data
- Limited flexibility for ad-hoc operational workloads
Trade-offs
Metrics
- Query latency (p95)
Time in which 95% of queries are answered; important for performance SLAs.
- Data freshness (time to availability)
Delay between event occurrence and availability in the warehouse.
- Data quality errors per period
Number of detected data quality rule violations within a period.
Examples & implementations
Retail: sales and inventory analytics
Consolidated warehouse combines POS, inventory and online sales data for demand forecasting and inventory optimization.
Finance: month-end closing and compliance
Financial data is historized and auditable to support regulatory reporting and reconciliations.
Healthcare: research and outcome analysis
Aggregated patient and treatment data enable longitudinal reporting and clinical analyses.
Implementation steps
Requirements analysis and definition of core KPIs
Design the data model and semantics
Build ingest, transform and load processes
Introduce monitoring, tests and data governance
⚠️ Technical debt & bottlenecks
Technical debt
- Legacy schemas without clear migration path
- Untested, undocumented ETL scripts
- Missing automation for pipeline deployments
Known bottlenecks
Misuse examples
- Attempting to use the warehouse as a primary streaming store
- Uncontrolled ingestion of all raw data without schema
- No versioning of ETL changes and model variants
Typical traps
- Underestimating effort for data cleansing
- Forgetting governance when scaling fast
- Ignoring cost model and storage types
Required skills
Architectural drivers
Constraints
- • Regulatory requirements for storage and access
- • Budget constraints for storage and processing
- • Legacy sources with heterogeneous formats