Reading and Understanding Data Schemas Questions
Be able to look at a data schema (table structure) and understand what data is available and how tables relate. At the start of the assessment, you'll be given a schema. Spend a minute understanding it before writing queries. Understand primary keys, foreign keys, and data types.
MediumTechnical
0 practiced
You're given tables: users, products, orders, order_items, promotions, product_categories. Describe how you'd determine which tables are 'fact' tables and which are 'dimension' tables to build a star schema. For the sales fact, specify the grain and list the keys and measures you would include. Mention any ambiguous cases and your reasoning.
MediumSystem Design
0 practiced
Given a transactions table with hundreds of millions of rows and most queries filter by transaction_date, propose a partitioning and indexing strategy (Postgres or Redshift) to improve query performance. Discuss maintenance considerations such as vacuuming, archiving old partitions, and maintenance windows.
MediumTechnical
0 practiced
You're handed a billing database and asked to define the business metric 'monthly-recurring-revenue (MRR)'. Describe the process to map schema columns to MRR: identify tables/fields, validate assumptions (pro-rated, trial periods), and produce a reproducible SQL definition or pseudocode for MRR calculation.
EasyTechnical
0 practiced
You're given the following simplified e-commerce schema:customers(customer_id PK integer, name varchar, email varchar, created_at timestamp)orders(order_id PK integer, customer_id integer FK -> customers(customer_id), total_amount decimal, placed_at timestamp)order_items(order_item_id PK integer, order_id integer FK -> orders(order_id), product_id integer, quantity integer, price decimal)Spend a minute examining the schema. List the primary keys and foreign keys, describe relationships between tables and their cardinality (one-to-many, many-to-one), and name which columns you would inspect first for data quality issues and why.
HardSystem Design
0 practiced
A column is proposed to be removed in production. Design a process to determine which dashboards, reports, and downstream jobs will be impacted by this schema change. Explain how you'd use metadata, SQL parsing of saved queries, dependency graphs, and stakeholder ownership to drive communication and remediation planning.
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