Advantages of the Django ORM
The ORM improves productivity with composable queries, model validation, and database abstraction.
- Readable query API
- Built-in escaping reduces SQL injection risk
- Easy relation traversal
Advantages of the Django ORM
Tagged with database
8 cards
How do transactions work in Django?
Django transactions group database operations so partial writes do not persist when an error happens mid-flow.
- Use transaction.atomic
- Good for multi-step writes
- Keep the transaction scope tight
How do transactions work in Django?
Why do Django migrations matter?
Migrations version the schema so database changes stay reproducible across environments.
- Model change to schema change
- Stored as code
- Supports rollback and history
Why do Django migrations matter?
Explain SQL joins
Joins combine rows from tables based on a related key, with inner and outer joins deciding what unmatched rows survive.
- INNER keeps matches
- LEFT keeps all left rows
- Join condition matters
Explain SQL joins
What are transactions?
Transactions group multiple statements into one atomic unit so partial updates do not leak through on failure.
- Begin commit rollback
- Protects consistency
- Works with isolation levels
What are transactions?
Database indexing in system design
Indexes speed up common queries, but they cost extra storage and slower writes.
- Optimize real query patterns
- Too many indexes hurt writes
- Composite indexes matter
Database indexing in system design
Database sharding basics
Sharding splits data across multiple databases so one machine does not hold or serve everything.
- Scale write and storage capacity
- Need shard key
- Cross-shard queries get harder
Database sharding basics
Primary-replica database setup
A primary handles writes while replicas serve copied data, often improving read scale and availability.
- Writes usually go to primary
- Replicas can lag
- Read/write split adds complexity
Primary-replica database setup