ADE Data Modeling & Schema Design 2

Question 1

In the context of data lakes and big data, what does 'schema-on-read' mean?

Accepted Answer

The schema is applied and interpreted when data is queried or read

Answer

The schema is enforced when data is written to storage

Answer

The schema is validated by a central metadata catalog

Answer

The schema is automatically inferred and stored in the file header

Question 2

Which partitioning strategy is most effective for time-series event data that is queried by date range?

Accepted Answer

Range partitioning on an event timestamp column

Answer

Hash partitioning on a user ID column

Answer

List partitioning on a country code column

Answer

Round-robin partitioning across all available nodes

Question 3

What is a materialized view and how does it differ from a standard view?

Accepted Answer

A materialized view stores pre-computed query results on disk; a standard view is a virtual query alias

Answer

A materialized view executes the query at runtime; a standard view stores pre-computed results

Answer

A materialized view only works with columnar storage; a standard view works with row storage

Answer

A materialized view cannot be refreshed; a standard view is always up to date

Question 4

In entity-relationship (ER) modeling, a 'many-to-many' relationship between two entities is typically resolved by:

Accepted Answer

Creating a junction (bridge) table with foreign keys to both entities

Answer

Adding a foreign key column to one of the two tables

Answer

Merging the two entities into a single wide table

Answer

Adding a composite primary key to one entity

Question 5

What is the primary advantage of columnar storage formats (e.g., Parquet, ORC) for analytics workloads?

Accepted Answer

They compress and read only the columns referenced in a query, reducing I/O

Answer

They allow faster single-row lookups by primary key

Answer

They enforce ACID transactions across all write operations

Answer

They replicate data automatically across multiple nodes

Question 6

In the Data Vault modeling approach, which component stores descriptive attributes and their historical changes?

Accepted Answer

Satellite

Answer

Hub

Answer

Link

Answer

Bridge

Question 7

Cardinality in data modeling most directly refers to:

Accepted Answer

The number of unique values in a column or the nature of a relationship between entities

Answer

The number of indexes defined on a table

Answer

The physical size in bytes of a table's storage footprint

Answer

The number of foreign keys pointing to a dimension table