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What is a data warehouse?

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Overview

A data warehouse is a central repository designed to store, organize, and analyze large volumes of data from multiple sources.

It's designed to support business intelligence, reporting, and advanced analytics, enabling organizations to make faster, more informed decisions. Whether you're analyzing customer behavior, forecasting inventory, or tracking financial performance, a data warehouse provides a reliable foundation.

Data warehouse

Why data warehouses matter in a modern enterprise

Modern enterprises rely on data warehouses to unify siloed data and deliver accurate, timely insights.

Unlike traditional databases built for day-to-day operations, data warehouses are optimized for complex queries, long-term trend analysis, and high-speed reporting across departments and systems.

Organizations generate vast amounts of data—from ERP systems, CRMs, IoT devices, e-commerce platforms, and external sources such as market feeds and social media. Without a centralized approach to collecting and organizing that data, it remains fragmented, inconsistent, and underutilized.

A well-designed modern data warehouse not only cuts reporting from days to seconds, it also helps:

  • Break down data silos across business units
  • Accelerate insights from historical and real-time data
  • Enable secure, governed access to trusted data
  • Support compliance with industry and regional regulations

Key benefits of a data warehouse

Companies that centralize their analytics in a data warehouse see measurable improvements: faster queries on terabytes of data, fewer manual reconciliations, and higher confidence in KPIs pulled across multiple business units.

  • Centralized access: Consolidate data from disparate systems and applications.
  • Faster performance: Optimize query speed for complex, large-scale analytics.
  • Accurate reporting: Use historical data for trusted metrics and KPIs.
  • Improved data quality: Enforce validation, cleansing, and transformation rules.
  • Scalable decision-making: Empower business users and analysts with self-serve tools.

Data warehouse architecture explained

Every analytics process runs through five core layers—ingestion, staging, storage, querying, and governance. Understanding each layer helps pinpoint slowdowns, control costs, and improve query accuracy.

  • Data ingestion: Extract, transform, and load (ETL/ELT), or load-then-transform, data from source systems.
  • Storage layer: Organize data into schemas optimized for analytics.
  • Metadata management: Track data lineage, context, and structure.
  • Query layer: Interface with BI tools, APIs, or SQL engines.
  • Governance & security: Control access, compliance, and auditability.

Understanding the architecture helps clarify how data flows through your systems—from ingestion to analysis—and highlights where performance, scalability, and governance matter most.


Types of data warehouses

The right type of data warehouse depends on how quickly you need access to data, who’s using it, and what decisions it’s powering. From centralized, long-term analytics to fast operational reporting or department-level views, each model supports a different set of priorities.

  • Enterprise data warehouse (EDW): A centralized, integrated repository that spans the business.
  • Operational data store (ODS): A more agile repository for short-term or near-real-time needs.
  • Data marts: Subsets of a data warehouse tailored to individual departments or use cases.

Schemas in data warehouses

Schemas define how data is structured for querying. The right choice affects speed, storage efficiency, and ease of reporting.

  • Star schema: A central fact table linked to dimension tables for simplicity and speed.
  • Snowflake schema: Normalized dimension tables reduce redundancy but can increase query complexity.
  • Galaxy schema: A schema with multiple fact tables sharing dimension tables, often used when dealing with interconnected business processes.

You can get improved query performance, enhanced data analysis, simplified data management and flexibility based on your business needs.


Data warehouse vs database: What's the difference?

While traditional databases handle real-time transactions and operational data, data warehouses are purpose-built for analyzing large volumes of historical data. Understanding the distinction helps teams choose the right platform for performance, scale, and insight.

Feature Traditional database Data warehouse
Purpose Daily transactions (OLTP) Historical analysis (OLAP)
Data volume Lower Higher
Query complexity Simple Complex, multi-source
Update frequency Constant Periodic
Users Operations teams Analysts, decision-makers

Data warehouse, data lake, or lakehouse?

The decision comes down to structure versus flexibility. Warehouses excel at governed, repeatable analytics; lakes offer raw data freedom; lakehouses aim to balance both.

  • Data warehouse: Structured, curated data for analysis.
  • Data lake: Raw, unstructured, or semi-structured data for flexibility.
  • Lakehouse: A hybrid approach that combines both models.

Key use cases for data warehousing

From customer lifetime value analysis to predicting supply chain delays, data warehouses power the analytics that drive measurable business results.

  • Customer analytics: Track behavior, retention, and churn across channels
  • Sales & marketing: Align pipeline performance with marketing attribution
  • Finance: Analyze P&L, budgets, forecasts, and compliance
  • Supply chain: Predict disruptions and optimize procurement
  • Operations: Drive efficiency through asset and process insights

See how GUESS achieved 400x faster queries, expanded from 3 TB to 36 TB, and empowered 80% of global staff with insights using OpenText Analytics Database.


Cloud, hybrid, and modern deployment trends

Cloud-native warehouses scale on demand, hybrid setups balance security and flexibility, and multi-cloud strategies optimize compliance and resilience.

  • Cloud-native platforms scale easily and support real-time ingestion.
  • Hybrid deployments combine on-prem systems with cloud analytics.
  • Multi-cloud architectures enable regional compliance and workload balancing.

How to choose the right data warehouse

Map your current data sources, growth projections, and query needs. The best choice will scale to handle 10–100x more data and users without performance loss.

  • Deployment model: On-premises, cloud, or hybrid.
  • Performance requirements: Concurrent users, query speed, uptime.
  • Data volume: Scalability and storage format (columnar vs row).
  • Security and compliance: Encryption, user roles, data sovereignty.
  • Integration: Compatibility with BI tools, APIs, data sources.

How can OpenText help you take advantage of data warehouse benefits?

A data warehouse is only as valuable as the insights it delivers—and that depends on speed, accessibility, and trust in the data. OpenText Analytics Database (Vertica) helps you maximize these benefits by combining enterprise-grade performance with built-in governance and advanced analytics capabilities.

With OpenText, you can:

  • Shorten time to insight – High-performance query execution means analysts can run complex reports on billions of records in seconds, not hours.
  • Break down silos faster – Seamless integration with multiple data sources, including legacy systems, APIs, and cloud platforms, ensures your warehouse reflects a complete, up-to-date view of the business.
  • Maintain trusted data – Embedded data quality, lineage tracking, and validation workflows help ensure every decision is based on accurate, verified information.
  • Scale without performance loss – Elastic scaling supports growing workloads, higher user concurrency, and larger datasets without slowing queries.
  • Enable advanced analytics – Built-in AI, machine learning, and predictive modeling allow teams to move from descriptive to prescriptive insights.
  • Stay compliant and secure – Enterprise-level encryption, access controls, and audit logging protect sensitive data and support regulatory requirements.
  • Deploy with flexibility – Based on your needs or architecture, you can choose among on-prem, hybrid, private cloud.

By combining your data warehouse with OpenText’s analytics and governance tools, you get a platform that not only stores and organizes data but also turns it into a strategic asset—ready to drive measurable business outcomes.

The cloud repatriation shift: What the data tells us

200+ IT leaders are rethinking cloud-only strategies for their data warehouses—opting for on-prem, private cloud, or hybrid deployments to reclaim performance, cost-efficiency, and control.

Get the guide

Footnotes