Class 4

Question 1

semiadditive facts

Answer 1

they may be added at end of day, can’t add across some dimensions but not all such as time, bank balance

Question 2

4 steps in the dimensional modeling process

Answer 2

Step 1: Select Business Process
Step 2: Declare Grain
Step 3: Identify Dimensions
Step 4: Identify Facts

Question 3

natural keys

Answer 3

could be origonal source data that can be used as a key.

Question 4

degenerative dimensions

Answer 4

POS transactions, measures that don’t have own dimensions. the attributes may be captured by other dimensions. transaction number, telephone number.

Question 5

factless fact table

Answer 5

doesnt contain a fact.

Question 6

bridge table

Answer 6

connects 2 tables. many to many relationship between 2 tables, need a composite key, so you add foreign key of both . so its a type of fact table.

Question 7

rollup

Answer 7

subset of cube. 
rollup (custid, produd, storeid)
create customer product store
            customer product
             customer
different sequence will create diff tables in rollup. 
in cube it does all of them.

Question 8

cube command

Answer 8

crate tables customer, product, store
                     customer, product
                     product, customer, store
                     store, and on.
all different combinations can be done.
it's doing all combination of tables.