Aug 7, 2025
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3 min to read
What Is a Data Warehouse? Modern Architecture, ROI, and Build Guide
Learn the modern data-warehouse stack, when to choose Snowflake vs BigQuery, and a 5-step plan to build one that’s AI-ready.

Ali Z.
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CEO @ aztela
TL;DR: A data warehouse is the single, trusted home for all analytics data built to answer business questions fast and feed AI models reliably.
Legacy definitions are everywhere. This guide is different:
Plain-English explanation for execs and non-engineers
Modern stack examples (Snowflake, BigQuery, Databricks)
ROI math to justify the project
5-step build playbook you can start next sprint
1. Data Warehouse vs Database vs Lakehouse
Feature | OLTP DB | Classic DW | Lakehouse |
---|---|---|---|
Optimized for | Transactions | Analytics | Hybrid |
Schema | Strict | Star/Snowflake | Flexible |
Cost scaling | $$$ | $$ | $–$$ |
AI-readiness | Low | Medium | High w/ ML features |
Key takeaway: If you need governed, query-ready data for BI + AI prototypes, a cloud DW or lakehouse is the pragmatic choice.
2. What Does “EDW” Actually Mean?
EDW = Enterprise Data Warehouse.
Same core idea, bigger scope: cross-department KPIs, compliance, and historical snapshots.
3. Why Modern Teams Choose Snowflake & BigQuery
Snowflake → Elastic compute, pay-as-you-go, strong ecosystem
BigQuery → Serverless, no-ops scaling, seamless with Google stack
Databricks Lakehouse → Combines warehouse SQL + Spark ML workflows
4. 5-Step Build Playbook (90-Day Roadmap)
Week | Milestone | Owner Tips |
---|---|---|
1 | Source inventory & KPI shortlist | Use our Data Audit Sheet (download) |
2-3 | Ingest via Fivetran/Airbyte | Load raw, don’t transform yet |
4-6 | Model in dbt: staging → marts | Add tests (not-null, freshness) |
7-8 | Build BI layer (Looker/Sheets) | Map each chart to a metric owner |
9-12 | Add DQ monitors & cost guardrails | dbt-tests + Warehouse usage views |
5. Cost & ROI Snapshot
Input | Range | Note |
---|---|---|
Cloud warehouse | $400-$4 k/mo | Usage-based; Snowflake credits or BigQuery slots |
Ingestion | $150-$1 k/mo | Fivetran standard SaaS connectors |
Team hours | 160-240 | ~1 FTE or fractional squad |
Total Year-1 | $30-$80 k | versus 3-5× for on-prem EDW |
ROI lever: A single trusted churn KPI that cuts cancellation 5 % on $4 M ARR = $200 k saved—2-6× project cost.
6. Data Warehouse vs Lakehouse—Which to Choose in 2025?
Need heavy ML + streaming? Go Lakehouse.
Primarily dashboards + ad-hoc SQL? Warehouse first, layer Lakehouse later.
Frequently Asked Questions
What is a data warehouse in simple terms?
A central database optimised for fast analytics queries, storing cleaned, historical data from across the business.
Is Snowflake a data warehouse?
Yes. Snowflake is a fully managed cloud data-warehouse platform that separates storage and compute for elastic scaling.
How long does it take to build a data warehouse?
With modern cloud tools and a focused scope, you can deliver a usable MVP in 8-12 weeks.
Ready to Build Yours in 90 Days?
We implement the playbook above for mid-market, enterprise—AI-ready from day one.
Looking to become data & AI-led
Looking for how to move from legacy to cloud
Looking to gain visibility in your most important metrics, and insights.
👉 Book a free data-warehouse roadmap call get a tailored build plan in 30 minutes.
Content
FOOTNOTE
Not AI-generated but from experience of working with +30 organizations deploying data & AI production-ready solutions.