Discussion
Which of the following statement(s) is/are true ?
(i) Dimension tables of star schema models are brought to normalized form to reduce redundancy.
(ii) Snowflake structure can reduce the effectiveness of browsing since more joins are needed for query.
Answer: B
Only statement (ii) is true, so the answer is (ii) only.
In a star schema the dimension tables are deliberately kept denormalised: each dimension is one wide table joined directly to the fact table, trading some redundancy for simple, fast queries. Normalising the dimension tables into sub-tables is exactly what turns a star schema into a snowflake schema, so statement (i) is false as a description of the star model.
Statement (ii) is true: because a snowflake splits each dimension into several tables, a query must make more joins, which reduces the effectiveness of browsing the dimensions.
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