Question { ITC Infotech, 83135 }

What are the different types of schemas?

Answer

three types of schemas are availble.Star schema,star flake
schema & snow flake schema.

Star schema:It is highly denormalised,so we can retrieve
the data very fast.

Star flake schema:Only one dimension contain one level of
hierachy key.

Snow flake schema:It is highly normalised,so retrievel of
data is slow.

Question { 5236 }

scd methodology?

Answer

Type1: No historical datas will be available, when changes
are made the old data will be deleted and the new data will
be insrted.

Type2: Flag:The old data will be denoted as false and the
new data will be denoted as true.

Version:The changes made will be numbered as 0,1,2...so on.

Date:The changes along with the date in which they are made
are clearly mentioned.

Type3:The latest change which is made is alone available.

Question { 15963 }

what is scd?

Answer

The datas are kept in the data base
through the slowly changing dimension process.There are
three types in slowly changing dimensions:
type1,type2.type3.