Find out what you really know
Reading a lesson feels like learning. Answering without it open is how you find out. Incidents to work through, quizzes that explain every answer, and mock interviews for data roles, with your progress kept in this browser. No account.
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What is the purpose of Python lists?
Not this time. Python lists are used to store multiple items in a single variable.
Scenarios
An incident with AI, an agent or a data system, the evidence, and the calls to make. Then what really went wrong.
- How AI works · beginnerThe AI test that passes on Monday and fails on TuesdayA test of an AI feature fails about 1 run in 6, and since a model upgrade it fails most runs. Nothing in the code changed. Find out why, and write a test that means something.
- Data engineering in the AI era · beginnerThe revenue dashboard that is 17% too highApril revenue on the sales dashboard is 17.2% above finance's figure, and the board meeting is at 14:00. Find the cause in the query, not in the warehouse.
- How AI works · beginnerThe warranty the help bot inventedA customer was promised a 2-year warranty on a refurbished laptop. There is no such warranty. Work out why the bot said it, and what stops the next one.
- AI agents · intermediateThe agent bill that grew 5 times in a monthA coding agent's monthly bill went from $1,200 to $6,700 while the number of tasks rose by a fifth. Find where the money went before you cut the wrong thing.
Quizzes
- PythonBeginnerStart Every Python quiz
- SQLBeginnerStart Every SQL quiz
- PySparkExpert · Beginner · IntermediateStart Every PySpark quiz
- DatabricksBeginner · IntermediateStart Every Databricks quiz
- GenAIBeginner · IntermediateStart Every GenAI quiz
- ReactBeginner · IntermediateStart Every React quiz
- AWSBeginnerStart Every AWS quiz
Mock interviews
Data engineering in the AI era still comes down to Spark, SQL, the cloud and the platforms on top. Pick your role, then the technology.
Data Engineer
- Databricks
- How does Delta Lake ensure ACID compliance on Databricks?
- Explain the difference between Apache Spark and Databricks
- AWS
- What are the core components of the AWS data lake architecture?
- What is the difference between batch processing and stream processing? Provide examples of AWS services used for each.
- Azure
- A pipeline copies data from Blob Storage to Azure SQL Database. If the source file schema changes (e.g., a new column is added), how can ADF handle this without manual intervention?
- How can you ensure data consistency when updating a Delta Lake table in Azure Data Lake Storage Gen2 using ADF, especially when dealing with concurrent updates?
- PySpark
- What are RDDs, and how are they different from DataFrames and Datasets?
- What is a Spark job, and what are stages and tasks within it?
- SQL
- Can a table have multiple primary keys?
- Can a table have multiple UNIQUE constraints?
Data Analyst
- Databricks
- What is a Databricks cluster?
- Barbara needs to join data from a Delta table with data residing in a cloud storage location. How can this be efficiently accomplished within a Databricks notebook, considering data access patterns and potential performance bottlenecks?
- AWS
- What are the core components of the AWS data lake architecture?
- What is the difference between batch processing and stream processing? Provide examples of AWS services used for each.
- SQL
- Can a table have multiple primary keys?
- Can a table have multiple UNIQUE constraints?
Data Scientist
- General
- In the context of the Azure OpenAI Service, what distinguishes fine-tuning from prompt engineering as methods for adapting pre-trained models?
- Databricks
- How does Delta Lake ensure ACID compliance on Databricks?
- Distributed training with Horovod on Databricks. Does it automatically parallelize any ML model?
- AWS
- What are the core components of the AWS data lake architecture?
- What is the difference between batch processing and stream processing? Provide examples of AWS services used for each.
- Azure
- Azure Cognitive Services. Are they only accessible via REST APIs?
- What are the primary methods for deploying machine learning models as web services in Azure?
- SQL
- Can a table have multiple primary keys?
- Can a table have multiple UNIQUE constraints?
Prompt Engineer
- General
- What are some key principles for crafting effective prompts for large language models (LLMs)?
- How can you evaluate the quality of a prompt?
- Databricks
- How can you use prompt engineering to improve data quality checks within a Databricks notebook using LLMs?
- How can you leverage LLMs and prompt engineering to generate or explain Spark SQL code in Databricks?
Preparing for a certification?
A free sample in the style of the real exam, with its format and what it covers. The full mock exam is on Daily Bytes.