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.