AI GLOSSARY
Data Warehouse
A data warehouse is the traditional central repository for company-wide reporting and analytics data. It provides consistent metrics and a single source of truth—the foundation for sound decision-making. Modern cloud warehouses and lakehouses expand on this concept by adding flexibility and AI capabilities.
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Core Layers
Staging, Core, Data Marts, Semantics
Modeling Approaches
Star, Snowflake, Data Vault, Wide Table
Cloud Platforms
Fabric, Snowflake, Redshift, BigQuery, Synapse
Weeks
until the first production-ready dashboard
Why a Data Warehouse Remains Relevant for Mid-Sized Businesses
Even in the age of data lakes and lakehouses, the data warehouse concept remains relevant—as a clearly structured layer for reliable metrics. For small and medium-sized businesses, it is the pragmatic path to reporting, forecasting, and a consistent basis for decision-making.
Single Source of Truth
One definition per metric—trust is built, and debates disappear.
Lightning-Fast Reports
Optimized structures deliver dashboards in seconds instead of minutes.
Historical Data Set
All analyses draw on consistent historical data—enabling trend analyses.
Department-friendly
SQL and BI tools directly on the data warehouse—no data engineering required.
Compliance-ready
Clearly structured access and audit concepts — GDPR-compliant.
AI Integration
Data warehouse as a feature store and training source for ML models.
What is a data warehouse?
A data warehouse (DWH) is a central database that collects data from various sources (ERP, CRM, production, external feeds), transforms it, and makes it available for reporting and analytics.
Unlike operational databases, a DWH is optimized for queries and analytics —not for transactions. Data is typically stored in a clearly structured model (star or snowflake schema, Data Vault).
Traditional DWH solutions such as Oracle, SQL Server, or Teradata are increasingly being replaced by cloud data warehouses: Snowflake, Amazon Redshift, Google BigQuery, and Azure Synapse. They are more scalable, more cost-effective, and significantly more flexible.
For small and medium-sized businesses, a modern, cloud-based data warehouse or lakehouse is now standard—serving as the foundation for reporting, forecasting, and integration with AI models.
Modeling Approaches & Techniques
A data warehouse uses proven modeling techniques. These eight are particularly important in practice:
Star Schema
Snowflake Schema
Data Vault
Slowly Changing Dimensions
ELT Instead of ETL
Semantic Layer
Column Store
Materialized Views
Best Practices for Data Warehouse Projects
These six principles help ensure successful data warehouse projects:
- Business value first: Don’t be technology-driven—key metrics and reports set the direction.
- Iterative rather than a “big bang”: Start with one business unit—demonstrate success, then move on.
- Clear modeling: Star schema or Data Vault—no haphazard growth.
- Think cloud-native: Elastic compute resources—pay only for what you use.
- Implementa semantic layer early: Define key metrics consistently—this prevents conflicting figures.
- Incorporate governance from the start: Set up permissions, a catalog, and lineage right from the beginning.
Approach 1
Traditional DWH
Oracle, SQL Server, Teradata. Proven, but less flexible. On-premises or in a legacy cloud.
Legacy
Approach 2
Cloud DWH
Snowflake, Redshift, BigQuery, Synapse. Elastic, scalable, modern standard.
Cloud Standard
Approach 3
Lakehouse DWH
Fabric OneLake, Databricks. Data warehouse features in the lake. The path to the future.
Future
Common Mistakes in Data Warehouses
We often see these pitfalls:
- No clear data model: Haphazard merging leads to inconsistent reports.
- Models that are too large: “All-in-one” data warehouses fail—build them incrementally.
- Lack of historical data: Without SCD, comparisons over time are impossible.
- On-premises instead of the cloud: Legacy warehouses scale poorly—the cloud is usually the better choice.
- No governance strategy: Chaos in permissions and definitions—trust declines.
Data Warehouse vs. Data Lake vs. Lakehouse
Three approaches with clear strengths—combined in modern landscapes:
- Data Warehouse: Structured data, optimized for BI and reporting. Traditional, reliable.
- Data Lake: All data formats in object storage. Flexible and cost-effective—but without structural guarantees.
- Lakehouse: A combination — the structure of the warehouse, the flexibility of the lake. The modern standard.
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Frequently Asked Questions About Data Warehouses
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What is the difference between a data warehouse and a data lake?
A data warehouse stores structured, modeled data for reporting. A data lake accepts all formats—including unstructured data. A lakehouse combines both.
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As a small-to-medium-sized business, do I need a data warehouse?
As soon as multiple sources (ERP + CRM + others) need to be consolidated: yes. Modern cloud data warehouses make getting started quick and affordable.
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Which cloud data warehouse is the right one?
For customers with close ties to Microsoft, it's usually Microsoft Fabric or Synapse. For multi-cloud setups, it's often Snowflake. BigQuery for GCP customers.
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How long does a data warehouse project take?
First productive reports in 6–12 weeks. A comprehensive data warehouse grows over months and years. An iterative approach is key.
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How much does a cloud DWH cost?
Scalable — You pay for compute and storage. Small setups start at 500 EUR/month; large enterprise installations run into the five-digit range per month. Cost management is essential.
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How is a data warehouse related to BI?
A data warehouse is the foundation of business intelligence. Without a clean data warehouse foundation, there can be no reliable reports.
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When should I build a lakehouse instead of a warehouse?
If you also want to incorporate unstructured data (images, logs, videos) or machine learning. For pure BI, a traditional cloud data warehouse is often sufficient.
Data Warehouse for Your Reporting
In a free initial consultation, we’ll review your data landscape and assess the right data warehouse or lakehouse architecture for your needs—including a cost estimate.
As a data and AI partner for small and medium-sized businesses, we’ll build your data warehouse in a pragmatic way—with a focus on rapid business value and future-proofing.
What We Offer
- BI Consulting — The data warehouse as the foundation of your BI landscape.
- Software & Pipelines — ETL/ELT and data integration.
- AI Consulting — The data warehouse as a feature store for machine learning.
- Lakehouse in the Glossary — the modern alternative.