Database Fundamentals and Data Modeling Questions

Encompasses foundational database concepts and techniques for designing and querying data stores. Topics include relational database concepts, structured query language fundamentals for selecting and modifying data, schema design with tables and relationships, normalization principles, entity relationship modeling, indexing and basic performance considerations, transactions and data integrity, constraints and data types, and common operational tasks such as migrations, backups, and simple optimization strategies. Also discusses trade offs with nonrelational stores and when to choose different persistence models.

EasyTechnical

30 practiced

Describe common backup strategies for relational databases: full backups, incremental/differential backups, and point-in-time recovery (PITR). Explain pros/cons and the typical recovery steps for each strategy when dealing with accidental data deletion or corruption.

MediumTechnical

33 practiced

You need to add a NOT NULL column 'status' with default 'active' to a 2TB 'users' table with minimal downtime. Describe a migration plan including how to add the column, backfill efficiently, keep reads/writes compatible during rollout, and safely enforce NOT NULL in production.

MediumSystem Design

40 practiced

Design options for a multi-tenant SaaS database: single shared schema with tenant_id, one schema per tenant, and one database per tenant. Compare isolation, cost, scaling, backup complexity, and query performance for each approach, and recommend when to use each option.

MediumSystem Design

33 practiced

Compare shard-by-user-id, shard-by-region, and functional sharding (service owns its data) for horizontal partitioning. For each approach describe rebalancing complexity, hotspot risk, operational complexity, and cross-shard query cost.

HardTechnical

29 practiced

You need to produce an analytics report that joins users (sharded by user_id) with orders (sharded by order_id). Design strategies to perform cross-shard joins efficiently, considering network cost, staleness, and consistency, and recommend one approach for recurring daily reports vs ad-hoc queries.

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