Abstraction: the process of removing physical, spatial, or temporal details or attributes in the study of objects or systems to focus attention on details of greater importance; it is similar in nature to the process of generalization.
Data extraction is the act or process of retrieving data out of (usually unstructured or poorly structured) data sources for further data processing or data storage (data migration).
Data mining is a process of discovering patterns in large data sets involving methods at the intersection of machine learning, statistics, and database systems.

→ ​ Data warehouse is subject oriented, integrated, time variant, nonvolatile collection of data in support of management decisions.
→ A data warehouse (DW or DWH), also known as an enterprise data warehouse (EDW), is a system used for reporting and data analysis, and is considered a core component of business intelligence.
→ DWs are central repositories of integrated data from one or more disparate sources. They store current and historical data in one single place that are used for creating analytical reports for workers throughout the enterprise.

→ A data warehouse is a subject-oriented, integrated, time-variant and non-volatile collection of data in support of management's decision making process.
Subject oriented:​ A data warehouse can be used to analyze a particular subject area. For example, "sales" can be a particular subject.

→ ​ Top-Down​ is also known as Inmon’s Top Down Approach, data warehouse is built first. Inmon defines a data warehouse as a centralized repository for the entire enterprise. Dimensional data marts are created only after the complete data warehouse has been created.
→ ​ Bottom-Up​ is also called as Kimball’s bottom up approach, the most important business aspects or departments, data marts are created first. A data mart provide a thin view into the organisational data and addresses a single business area. These data marts are then integrated into larger data warehouse to build a complete data warehouse. The integration of data marts is implemented using Kimball’s data warehousing architecture which is also known as data warehouse bus (BUS).