What is Data Warehouse?
A data warehouse is a central database designed for reporting and analysis, which collects cleaned data from many source systems in one place.
Data Warehouse explained
Operational systems such as a billing tool, a CRM or a website database are built to record transactions quickly. A warehouse is built the other way round: it stores history from all those systems in a consistent structure, optimised for questions that scan many rows, such as revenue by region over three years.
Data usually arrives through a pipeline (ETL or ELT) on a schedule, and is organised into tables that analysts and BI tools query with SQL. Popular examples include BigQuery, Snowflake and Amazon Redshift, though a well-indexed PostgreSQL database can serve a small business the same way.
Example
A retailer copies orders from its shop platform, stock levels from its warehouse system and ad spend from its ad accounts into one warehouse every night, so finance can see margin by product without opening three tools.
How it differs from similar terms
A data lake stores raw files in any format; a warehouse stores structured, modelled tables ready for queries.
Asking about it in plain English
With SchemaChat you can type a question about your own data instead of writing a query, and check the SQL and figures it used before you rely on the answer. For example:
- What was revenue by region for each quarter this year?