A data warehouse helps solve the on-going problem of pulling large amounts of data from disparate sources like transactional or operational systems quickly and efficiently and transforming that data for optimised reporting. A Data warehouse also allows for the processing of large and complex queries in a highly-efficient manner.
To move data into a data warehouse, data is periodically extracted from multiple disparate sources that contain essentially information. As the data is moved, it can be cleaned, transformed, summarised, and reorganised. The data can be stored in the lowest level of detail, and have aggregated views available in the warehouse for easy extraction and analysis. A data warehouse becomes a permanent data store used to meet reporting and data analysis needs.
There are limits to how much data can be imported into a Power BI Desktop file, likewise there are also limits to the size of a Power BI Workspace, where the Power BI Desktop files are published for consumption in the Power BI service.
As a data warehouse is not reporting tool agnostic, nor does it confine to the data storage limitations of many reporting tools. When investing in a DW, you are not investing in a specific reporting tool, rather, you are future proofing your IT investment through an investment into data efficiency which empowers a historical and coherent picture of your business at any point in time.
Whether you’re using Microsoft Power BI, or any other BI tool, for your data analytics needs, it is best practice to not expect the BI tool to handle the data model processes and for it to become a historical data base. BI tools like Power BI are built to provide business users an interactive platform for data analysis, they not to be viewed as data warehouse solution. Data mining, Data integration, complex ETL process and data cleaning, is the not the role of a BI tool, especially when it comes to the demands of enterprise operational data and reporting needs. Investing in data warehouse architecture that integrates data from multiple sources, even unstructured data, and models this in a structure optimized for reporting needs, frees the BI tools used to focus on analysing data instead. Having all your data consolidated into a well designed relational database, STAR scheme, places your organisation at a massive reporting advantage.