1. What is a staging area? 2. Why are users not allowed to interact with the staging area? 3. When should we use flat files in the staging area? 4. What is ETL, and when should it be applied? Solution Staging area is place where you hold temporary tables on data warehouse server. Staging tables are connected to work area or fact tables. We basically need staging area to hold the data , and perform data cleansing and merging , before loading the data into warehouse Other response activities that may occur at/near a staging area are: personnel and equipment sign-in and sign-out, a fi eld or forward command center, security, personnel and equipment decontamination, wildlife treatment, and responder break areas SAFETY • Staging areas should be monitored to ensure a safe environment. Consider the following hazards: - Aircraft and heavy equipment operations, - Slips, trips and falls, - Hypothermia, - Exposure to contamination and hazardous materials, - Heavy equipment and crane operations, - Hearing impairment, - Respiratory exposure, and - Eye protection. • Select PPE based on the incident-specifi c Site Safety Plan. Programmers use flat file databases when creating applications in Oracle and SQL, which support multiple programming languages. Because of their simple structure, flat files consume less space than structured files, but the information in flat files can only be read, stored and sent. Data representation in a flat file database complies with certain standards. Every column in a flat file database is restricted to a specific data type. ETL stands for Extract-Transform-Load and it is a process of how data is loaded from the source system to the data warehouse. Data is extracted from an OLTP database, transformed to match the data warehouse schema and loaded into the data warehouse database. Many data warehouses also incorporate data from non-OLTP systems such as text files, legacy systems and spreadsheets. Let see how it works For example, there is a retail store which has different departments like sales, marketing, logistics etc. Each of them is handling the customer information independently, and the way they store that data is quite different. The sales department have stored it by customer’s name, while marketing department by customer id. Now if they want to check the history of the customer and want to know what the different products he/she bought owing to different marketing campaigns; it would be very tedious. The solution is to use a Datawarehouse to store information from different sources in a uniform structure using ETL. ETL can transform dissimilar data sets into an unified structure.Later use BI tools to derive meaningful insights and reports from this data .