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.
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.
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.
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
User name and password is saved by Business objects when we
create repository. and this username and password is saved
in Table obj_m_actor table in repository. The password in
incrypted form. It is possible to Dycrypt That Password.
1.what is input level context and output level context in webI?
2.what is a cascading prompt? Where will you give this and how?
3. What is External Strategy?
in BO module, you forgot all password even all user in
business object, designer, supervisor, gen.supervisor
everythicg, how to you recover your datas?