DA0-002 Data Concepts and Environments Practice Test 9 — 15 Questions

Question 1

A company is ingesting data from multiple sources into a cloud data warehouse. They decide to load the data raw and then perform transformations within the warehouse. Which approach does this describe?

Choose an answer to begin — your selection is scored in the full session.

Accepted Answer

ELT. ELT (Extract, Load, Transform) loads raw data first, then transforms it inside the data warehouse, as opposed to ETL which transforms before loading.

Answer

Data lake ingestion

Answer

ETL

Answer

Stream processing

Question 2

A database administrator wants to ensure that every value in a column matches values in a primary key column of another table. Which constraint enforces this rule?

Accepted Answer

Foreign key. A foreign key constraint ensures referential integrity by requiring that values in a column match values in the primary key of another table.

Answer

Unique constraint

Answer

Primary key

Answer

Check constraint

Question 3

An analyst is reviewing a table that stores customer orders. The table contains columns: OrderID, CustomerName, Product1, Product1Qty, Product2, Product2Qty. This design violates which normal form?

Accepted Answer

First normal form (1NF). The table violates First Normal Form (1NF) because it contains repeating groups (Product1, Product1Qty, Product2, Product2Qty) instead of storing each product in a separate row. 1NF requires that each column contains atomic values and that there are no repeating groups or arrays. The presence of multiple product columns for a single order breaks this atomicity and normalization rule.

Answer

No violation

Answer

Third normal form (3NF)

Answer

Second normal form (2NF)

Question 4

A data engineer is designing a system to handle high-velocity clickstream data from a website. The system must allow low-latency writes and support key-value lookups. Which type of database is most appropriate?

Accepted Answer

Key-value store (e.g., Redis). A key-value store like Redis is optimized for high-velocity writes and low-latency key-value lookups, making it ideal for clickstream data.

Answer

Graph database (e.g., Neo4j)

Answer

Document store (e.g., MongoDB)

Answer

Wide-column store (e.g., Cassandra)

Question 5

Which of the following best describes a data mart?

Accepted Answer

A subject-specific subset of a data warehouse. A data mart is a subject-specific subset of a data warehouse, focused on a particular department or function.

Answer

A repository for raw, unprocessed data

Answer

An OLTP system for transaction processing

Answer

A tool for extract, transform, and load processes

Question 6

A company wants to share a dataset with external partners via an API. Which API type is typically used for web services and uses XML or JSON for messaging?

Accepted Answer

REST API. REST APIs commonly use JSON or XML for messaging, making them a standard choice for data sharing over the web.

Answer

GraphQL API

Answer

SOAP API

Answer

WebSocket API

Question 7

A database has a table 'Orders' with columns OrderID (PK), CustomerID, OrderDate, and a table 'OrderDetails' with OrderID (FK), ProductID, Quantity. To ensure that every OrderID in OrderDetails exists in Orders, which integrity constraint is enforced?

Accepted Answer

Referential integrity. Referential integrity, enforced via a foreign key constraint, ensures that values in the foreign key column (OrderID in OrderDetails) match values in the primary key column of the referenced table (Orders).

Answer

Entity integrity

Answer

Domain integrity

Answer

User-defined integrity

Question 8

A data analyst needs to extract data from a transactional database and load it into a data warehouse for reporting. Which process typically transforms the data before loading it into the warehouse?

Accepted Answer

ETL. ETL (Extract, Transform, Load) transforms data before loading it into the warehouse, which is common for traditional data warehousing.

Answer

Data virtualization

Answer

ELT

Answer

Data replication

Question 9

Which of the following is an example of unstructured data?

Accepted Answer

An image file. Unstructured data has no predefined schema. Images are a classic example of unstructured data.

Answer

A JSON file

Answer

A relational database table

Answer

A CSV file with rows and columns

Question 10

A data governance team is defining roles and responsibilities for data management. Which TWO of the following are common data governance roles? (Select TWO).

Accepted Answer

Data steward. Data owner and data steward are standard roles in data governance, responsible for data ownership and stewardship respectively.

Answer

Data scientist

Answer

Database administrator

Answer

Data analyst

Question 11

A company is designing a data pipeline to process streaming data from social media feeds. Which THREE of the following are characteristics of streaming data? (Select THREE).

Accepted Answer

Data is unbounded and infinite. Streaming data is inherently unbounded and infinite because social media feeds generate a continuous, never-ending flow of events. Unlike batch data, there is no natural end to the stream; new tweets, posts, or interactions arrive constantly, making the dataset theoretically infinite in size.

Answer

Data is processed in micro-batches

Answer

Data is stored permanently before processing

Question 12

A database designer wants to improve query performance on a large table that is frequently filtered by multiple columns. Which TWO types of indexes could be beneficial? (Select TWO).

Accepted Answer

Composite index. Composite indexes cover multiple columns, and B-tree indexes are general-purpose and support range queries, both useful for filtering on multiple columns.

Answer

Bitmap index

Answer

Hash index

Answer

Full-text index

Question 13

Which of the following data types best describes a JSON file containing customer orders with varying fields per record?

Accepted Answer

Semi-structured data. JSON is a semi-structured data format because it allows flexible schema where fields can vary between records.

Answer

Unstructured data

Answer

Structured data

Answer

Relational data

Question 14

A company needs to store raw data from IoT sensors for future machine learning projects. The data is expected to be massive and in various formats. Which storage solution is most appropriate?

Accepted Answer

Data lake. A data lake stores raw data in its native format without predefined schema, ideal for large volumes of varied data for future use.

Answer

Data mart

Answer

Data warehouse

Answer

Relational database

Question 15

An OLTP system processes thousands of transactions per second. Which property ensures that a transaction is fully completed or fully rolled back, preventing partial updates?

Accepted Answer

Atomicity. Atomicity guarantees that a transaction is treated as a single unit, completed entirely or not at all.

Answer

Isolation

Answer

Durability

Answer

Consistency