4. You are a data architect bidding for a new contract with a prestigious blue-chip organization. Part of the selection process is a technical interview. Answer the following questions from the interview panel. a) Describe the defining characteristics of a data warehouse and how it differs in content and purpose from an "OLTP database system. You should use your own suitable examples and/or diagrams as needed. |10] b) Explain. the term 'ETL' with respect to data warehouses, taking care to highlight common problems/issues in each stage. You should use your own suitable examples as needed. [10] c) Using examples of your choice differentiate between Star Schema and Snowflake Schema in Data Warehousing [5]