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Topic 6: ORM, Tooling, and Developer Productivity

ORMs, Schema Migrations, CI/CD, and Database Testing

Topic Overview

Object-relational mapping (ORM) frameworks abstract SQL behind object-oriented APIs, improving developer productivity but introducing performance risks when abstraction leaks. The object-relational impedance mismatch creates fundamental challenges: objects have identity, inheritance, and references, while relational tables use foreign keys and normalization. ORMs generate SQL automatically, which can produce inefficient queries (e.g., N+1 problems) that developers must detect and optimize. Schema migrations require careful management to avoid downtime and data loss in production. Database testing strategies must balance isolation (test containers) with realism (real database behavior). Students must evaluate when ORMs improve productivity versus when they introduce unacceptable performance costs, and understand how to manage schema evolution and testing in production systems.

Student Presentation Assignments

Student 1:ORMs – Power and Pitfalls

Required Coverage:

  • Must explain what ORMs solve, specifying abstraction benefits and quantifying developer productivity improvements where possible, analyzing ORMs as abstractions with inherent costs, not convenience tools
  • Must compare at least two ORMs (Hibernate, Django ORM, or SQLAlchemy), analyzing architecture differences and abstraction trade-offs, not merely listing framework features
  • Must explain object-relational impedance mismatch, specifying fundamental challenges (identity, inheritance, references) with examples
  • Must justify when ORMs help productivity, identifying scenarios (rapid development, type safety) with concrete benefits
  • Must analyze when ORMs hurt performance, specifying query generation problems and lazy loading issues with examples, including analysis of generated SQL, not just object model code
  • Must evaluate trade-offs: convenience vs control, abstraction vs optimization, specifying when each is preferable

Student 2:N+1 Query Problem

Required Coverage:

  • Must formally define the N+1 problem, providing executable examples focusing on query count and shape, not framework-specific syntax
  • Must explain how ORMs cause N+1 problems, specifying lazy loading behavior and relationship traversal patterns
  • Must compare detection methods (profiling, query logging, monitoring), analyzing effectiveness and overhead
  • Must compare eager vs lazy loading strategies, analyzing trade-offs in memory usage, query count, and performance
  • Must explain performance tuning techniques (e.g., eager loading, batch loading), analyzing underlying query patterns and specifying when each is appropriate, not providing framework-specific API tutorials
  • Must analyze at least one real-world example, explaining the problem encountered and solution implemented

Student 3:Schema Migrations & CI/CD

Required Coverage:

  • Must analyze schema migration challenges, specifying downtime risks, rollback complexity, and data loss scenarios
  • Must compare Flyway vs Liquibase, analyzing differences in versioning, rollback support, and operational features, focusing on migration design implications, not tool feature comparisons
  • Must explain zero-downtime migration strategies, specifying techniques (additive changes, dual writes) and limitations, presenting them as risk mitigation, not guarantees
  • Must explain rollbacks and safety checks, specifying validation approaches and testing strategies, including data correctness verification, not just schema state restoration
  • Must compare production deployment strategies (blue-green, canary, backward compatibility), analyzing trade-offs
  • Must explain CI/CD integration, specifying how to automate migration testing and deployment safely, focusing on database migration logic, not CI pipeline tutorials

Student 4:Database Testing & Version Control

Required Coverage:

  • Must explain treating schema as code, specifying version control best practices and how they differ from application code
  • Must evaluate version control practices (migration files, review processes), analyzing how they prevent production issues
  • Must compare unit tests vs integration tests, specifying when to use each and trade-offs in speed vs realism
  • Must explain test containers, analyzing how they provide isolated database testing and comparing with alternatives
  • Must evaluate mock vs real databases, analyzing trade-offs in speed, realism, and maintenance burden
  • Must explain testing data migrations, specifying how to ensure correctness and safety without production data

Presentation Requirements

All presentations must be 17–20 minutes in duration and include the following components:

Note: Presentations that only summarize definitions, list features, or copy diagrams without interpretation will receive low marks. Each presentation must demonstrate analytical reasoning through comparisons, trade-off analysis, and justification of design decisions. Reading slides verbatim or presenting material that could be satisfied by reading documentation will be penalized.

Report Requirement: In addition to the presentation, each student must submit an individual PDF report. See Seminar Report Requirements for format, content, and submission details.

Evaluation Criteria

Criterion Weight Description
Technical Correctness 30% Accuracy of technical content, correct use of terminology, absence of errors
Depth of Understanding 25% Goes beyond surface-level definitions, demonstrates system-level comprehension
Clarity and Structure 20% Logical flow, clear explanations, appropriate use of examples and visuals
Use of Examples and Trade-offs 15% Concrete examples, discussion of limitations, comparison with alternatives
Slide Quality and Time Management 10% Professional formatting, appropriate pacing, stays within time limit

Recommended References

Books:

Documentation:

Academic / Technical: