what is the difference b/w star and snowflack schema in
dataware house?
Answers were Sorted based on User's Feedback
Answer / shekar
Star schema: one fact table is sorrounded by de-normalised
dimension table. In star schema we dont have any extended
dimension tables.
Snow flake schema: one fact table is sorrounded by
ormalised dimension table.In Snowflake schema we can have
extended dimension tables.
Is This Answer Correct ? | 13 Yes | 0 No |
Answer / simha
i think ur answer is swap to both. star is
denormalised,snowflake is normalised.
Is This Answer Correct ? | 13 Yes | 2 No |
Answer / thava
Star schema is one fact table in the middle is sorrounded
by many dimension tables and no extenssion for the dimensin
table it means denormalized.
Snowflake schema is where the dimension table is extended
to normalized form
Is This Answer Correct ? | 6 Yes | 0 No |
Star Schema : Star Schema is a relational database schema
for representing multimensional data. It is the simplest
form of data warehouse schema that contains one or more
dimensions and fact tables. It is called a star schema
because the entity-relationship diagram between dimensions
and fact tables resembles a star where one fact table is
connected to multiple dimensions. The center of the star
schema consists of a large fact table and it points towards
the dimension tables. The advantage of star schema are
slicing down, performance increase and easy understanding of
data.
Snowflake Schema : A snowflake schema is a term that
describes a star schema structure normalized through the use
of outrigger tables. i.e dimension table hierachies are
broken into simpler tables.
In a star schema every dimension will have a primary key.
# In a star schema, a dimension table will not have any
parent table.
# Whereas in a snow flake schema, a dimension table will
have one or more parent tables.
# Hierarchies for the dimensions are stored in the
dimensional table itself in star schema.
# Whereas hierachies are broken into separate tables in snow
flake schema. These hierachies helps to drill down the data
from topmost hierachies to the lowermost hierarchies.
Is This Answer Correct ? | 4 Yes | 1 No |
Answer / pp
star schema is nothing but one fact table that is
associating with different dimension tables.
Is This Answer Correct ? | 7 Yes | 6 No |
Answer / buttguru
The difference is in dimension tables and not the fact
table. Star schema contains denormalized dimension tables
while snowflake schema contains normalized dimension
tables, ie dimension tables are extended in snowflake
schema.
Is This Answer Correct ? | 4 Yes | 3 No |
Answer / bhushanam
Star schema is a schema where the data is in normalized
form and snow-flake star schema the data is in
de-normalized form
Is This Answer Correct ? | 1 Yes | 18 No |
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