ppt-8

Question 1

view

Answer 1

virtual table made from other queries from BASE TABLES. different from join in that its “stored” in the db. seems mostly good for simplifying queries

Question 2

how to make a view

Answer 2

CREATE VIEW name AS [query here]

Question 3

view potential problems

Answer 3

• multi-table view cant really add new records

- cant use DISTINCT or GROUP BY in [query]

Question 4

data warehouse

Answer 4

big data used in decision making process

• subject oriented: one topic
• integrated: different data sources work together
• time-variant: able to look at time trends
• non updateable

Question 5

data mart

Answer 5

subset of the data warehouse that is used for a SPECIFIC problem e.g. sales, marketing, finance, etc.

Question 6

usefulness of data warehouse

Answer 6

excellent for long term decision making. doesnt have to be as efficient. better at long term trend analysis. improve performance by getting rid of operational data

Question 7

homogenous data

Answer 7

metadata, formatting, etc will be different when you collect from different sources. you need to consolidate them into one file

Question 8

independent data mart

Answer 8

data mart created straight from operational sources

Question 9

ETL

Answer 9

“extraction, transformating, and loading”

Question 10

dependent data mart

Answer 10

data mart completely created from an existing data warehouse

Question 11

logical data mart

Answer 11

only good for smaller databases.