In what scenarios would denormalization be preferred over normalization?

  • When data integrity is the primary concern
  • When data modification operations are frequent
  • When storage space is limited
  • When there's a need for improved read performance
Denormalization may be preferred over normalization when there's a need for improved read performance, such as in data warehousing or reporting scenarios, where complex queries are frequent and need to be executed efficiently.

In data extraction, what is meant by the term "incremental extraction"?

  • Extracting all data every time
  • Extracting data only from one source
  • Extracting data without any transformation
  • Extracting only new or updated data since the last extraction
Incremental extraction involves extracting only the new or updated data since the last extraction, reducing processing time and resource usage compared to extracting all data every time.

Scenario: You are designing a distributed system where multiple nodes need to communicate with each other. What communication protocol would you choose, and why?

  • Apache Kafka
  • HTTP
  • TCP/IP
  • UDP
Apache Kafka would be an ideal choice for communication in a distributed system due to its ability to handle large volumes of data streams efficiently and its fault-tolerant nature. Kafka's distributed architecture ensures high scalability and reliability, making it suitable for real-time data processing and communication between nodes in a distributed environment. Unlike HTTP, TCP/IP, and UDP, Kafka is specifically designed for distributed messaging and can support various communication patterns such as publish-subscribe and message queuing.

What are some common integrations or plugins available for extending the functionality of Apache Airflow?

  • Apache Hive, Microsoft SQL Server, Oracle Database, Elasticsearch
  • Apache Kafka, Docker, PostgreSQL, Redis
  • Apache Spark, Kubernetes, Amazon Web Services (AWS), Google Cloud Platform (GCP)
  • Microsoft Excel, Apache Hadoop, MongoDB, RabbitMQ
Apache Airflow offers a rich ecosystem of integrations and plugins for extending its functionality and integrating with various technologies. Common integrations include Apache Spark for distributed data processing, Kubernetes for container orchestration, and cloud platforms like AWS and GCP for seamless integration with cloud services. These integrations enable users to leverage existing tools and platforms within their Airflow workflows, enhancing flexibility and scalability.

Data modeling best practices emphasize the importance of maintaining ________ between different levels of data models.

  • Compatibility
  • Consistency
  • Flexibility
  • Integrity
Data modeling best practices emphasize the importance of maintaining consistency between different levels of data models to ensure that changes or updates are accurately reflected across the entire model hierarchy.

________ refers to the proportion of missing values in a dataset.

  • Data Density
  • Data Imputation
  • Data Missingness
  • Data Sparsity
Data Missingness refers to the proportion of missing values in a dataset. It indicates the extent to which data points are absent or not recorded for certain variables. Understanding data missingness is crucial for data analysis and modeling as it can affect the validity and reliability of results. Techniques such as data imputation may be used to handle missing data effectively.

What is the main difference between DataFrame and RDD in Apache Spark?

  • Immutable vs. mutable data structures
  • Lazy evaluation vs. eager evaluation
  • Low-level API vs. high-level API
  • Structured data processing vs. unstructured data processing
The main difference between DataFrame and RDD in Apache Spark lies in their approach to data processing. DataFrames offer structured data processing capabilities, while RDDs handle unstructured data and provide more low-level control.

The physical data model includes details such as ________, indexes, and storage specifications.

  • Constraints
  • Data types
  • Keys
  • Tables
The physical data model includes details such as data types, indexes, and storage specifications, which are essential for designing the underlying database structure and optimizing performance and storage.

Scenario: Your organization is planning to migrate its big data storage infrastructure to the cloud. As a data engineer, you need to recommend a suitable storage solution that offers high durability, scalability, and low-latency access. Which cloud storage service would you suggest and why?

  • Amazon S3
  • Azure Blob Storage
  • Google Cloud Storage
  • Snowflake
I would recommend Amazon S3 (Simple Storage Service) for this scenario. Amazon S3 offers high durability with its data replication across multiple availability zones, ensuring data resilience against hardware failures. It is highly scalable, allowing organizations to seamlessly accommodate growing data volumes. Additionally, Amazon S3 provides low-latency access to data, enabling quick retrieval and processing of stored objects. These features make it an ideal choice for migrating big data storage infrastructure to the cloud.

What are slowly changing dimensions (SCDs) in the context of data warehousing?

  • Dimensions in a data warehouse that change occasionally
  • Dimensions in a data warehouse that change rapidly
  • Dimensions in a data warehouse that change slowly
  • Dimensions in a data warehouse that do not change
Slowly Changing Dimensions (SCDs) in data warehousing refer to dimensions that change slowly over time, requiring special handling to track historical changes accurately. Common SCD types include Type 1 (overwrite), Type 2 (add new row), and Type 3 (add new column).