What is the primary purpose of a data warehouse?
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A. B. C. D.C
Consider using a data warehouse when you need to keep historical data separate from the source transaction systems for performance reasons. Data warehouses make it easy to access historical data from multiple locations, by providing a centralized location using common formats, keys, and data models.
Query both relational and nonrelational data.
Incorrect Answers:
D: Data warehouses don't need to follow the same terse data structure you may be using in your OLTP databases.
https://docs.microsoft.com/en-us/azure/architecture/data-guide/relational-data/data-warehousingThe primary purpose of a data warehouse is to provide a central repository of data from multiple sources that can be used for business intelligence and reporting purposes. This allows for complex queries to be executed on the data in order to extract insights and make informed decisions.
Answer A, "to provide answers to complex queries that rely on data from multiple sources," is correct because a data warehouse is specifically designed to store and manage large volumes of data from disparate sources, and make that data available for analysis and reporting. This is in contrast to operational databases, which are optimized for transaction processing and are not well-suited to complex analytical queries.
Answer B, "to provide transformation services between source and target data stores," is not correct because while data may be transformed and cleaned before being loaded into a data warehouse, this is not the primary purpose of a data warehouse. ETL (extract, transform, load) tools are often used to automate the process of moving data from source systems to the data warehouse, but the purpose of the data warehouse is not to provide transformation services per se.
Answer C, "to provide read-only storage of relational and non-relational historical data," is partly correct but doesn't capture the full purpose of a data warehouse. While it is true that a data warehouse is typically optimized for read-heavy workloads, and that historical data is often stored in a data warehouse for analysis and reporting, a data warehouse can also store real-time or near-real-time data, and may include both relational and non-relational data stores.
Answer D, "to provide storage for transactional line-of-business (LOB) applications," is not correct because this is the purpose of operational databases, not data warehouses. LOB applications typically require fast access to transactional data for day-to-day business operations, whereas data warehouses are optimized for analytical queries and reporting.
In summary, the primary purpose of a data warehouse is to provide a central repository of data from multiple sources that can be used for business intelligence and reporting purposes. Answer A best captures this purpose.