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Lessons (18)

• SQL Language, Identifiers & Data Types

  … Identity, sequence and UUID An identity/auto-increment column generates numeric values. A sequence is a reusable database …

• API Contracts, Gateways and Security

  … Authentication proves identity; authorization decides permission. Sessions are server-managed state; signed tokens carry claims but still need …

• DBMS Foundations, Keys & Normalization

  … keys identify records, dependencies guide normalization, and constraints enforce relationships](/img/database-interviews/foundations.svg) Q2, Q3 and …

• Time, Consistency and Distributed Transactions

  … Lamport clocks establish a causal ordering; vector clocks can identify concurrent updates. Network partitions can create split brain …

• Domain-Driven Design: Tactical Patterns

  … block One-line meaning Example --- --- --- Entity Has an identity that stays the same while its data changes Order …

• Normalization & Denormalization

  … Use BCNF when you can clearly identify a non-key determinant causing anomalies. Normal forms at a glance …

• DRY: Don't Repeat Yourself

  … Merging them couples things that should change independently. js // These look identical… const validateProductName = (name) = name.length 0 …

• Deployments, ReplicaSets & Rollouts

  … Decide deliberately. Key takeaways - A Deployment manages ReplicaSets , which keep a fixed number of identical pods running. - Labels …

• Authentication, Authorization & API Security

  … You let an app access your identity without giving it your Google password . - OAuth 2.0 = authorization : "this …

• React Hooks in Practice

  … 2. Only call hooks from React functions (components or custom hooks). Why? React identifies each hook by its …

• Why Kubernetes?

  … one or more containers running together Pods Deployment Keeps N identical pods running; handles rollouts Deployments Service A …

• How a Web Request Works

  … The server proves its identity with a certificate signed by a trusted authority, which is the padlock 🔒 in …

• SQL vs NoSQL Databases

  … each folder (document) holds everything about one thing, and folders don't have to look identical. ![Relational tables …

• Docker & Containers

  … Your app, its runtime (Node 22), libraries and config go into one standard box that runs identically on …

• Topics, Partitions & Offsets

  … order C2"] end A record is uniquely identified by (topic, partition, offset) . Keys decide the partition, and the …

• Deploying & Operating Microservices

  … v2 v2 v2 v2 ✅"] Blue-green Run two identical environments. Blue serves traffic; deploy to green , test it …

• Scaling, Load Balancing & Rate Limiting

  … A, B, C, A, B, C… Servers are identical Weighted round robin Bigger servers get more Mixed server …

• Domain-Driven Design: Strategic Design

  … Instead, each context has its own small model , sharing only an identity (the customer ID). Subdomain vs bounded …