Data Dynamics Inc Interview Questions and Answers

ROW_NUMBER(), RANK(), and DENSE_RANK() are SQL window functions for ranking rows in a dataset based on specified criteria.

• ROW_NUMBER(): Assigns a unique sequential integer to rows within a partition, starting at 1. Example: Ranking employees by hire date.

• RANK(): Assigns a rank to each row within a partition, with gaps in ranking for ties. Example: Ranking students by exam scores.

• DENSE_RANK(): Similar to RANK(), but wit...read more

Design a dashboard to visualize cloud storage cost savings for enterprise clients using metadata insights.

• Identify key metrics: Focus on storage usage, cost per GB, and data access frequency.

• Use visualizations: Implement bar charts for cost comparisons and line graphs for usage trends.

• Incorporate filters: Allow users to filter by department, project, or time period to identify specific savings opportunities.

• Highlight a...read more

Investigate sensitive file access claims by analyzing logs and visualizing access patterns geographically.

• 1. Gather access logs: Collect logs from file servers, including timestamps, user IDs, and IP addresses.

• 2. Identify allowed regions: Define the geographical boundaries where access is permitted based on client policies.

• 3. Geolocate IP addresses: Use a geolocation service to map IP addresses to their respective regi...read more

Design a REST API for uploading and processing file metadata with validations and error handling.

• Endpoint: POST /api/metadata/upload - for uploading file metadata.

• Request Body: Accept JSON format with fields like 'filename', 'filetype', 'filesize'.

• Validation: Check for required fields, valid file types (e.g., .jpg, .pdf), and file size limits (e.g., < 5MB).

• Error Handling: Return 400 Bad Request for validation errors...read more

LIFT JOIN enhances INNER JOIN by allowing for additional filtering based on specific conditions.

• INNER JOIN returns rows with matching values in both tables.

• LIFT JOIN allows for additional conditions to filter results post-join.

• Example: INNER JOIN could link 'files' and 'users' tables by user ID.

• LIFT JOIN could further filter files to only show those accessed in the last month.

Implement secure PLL data scanning using encryption, access control, and distributed processing techniques.

• Use encryption for data at rest and in transit to protect sensitive PLL data.

• Implement role-based access control (RBAC) to restrict data access to authorized users only.

• Utilize distributed processing frameworks like Apache Spark for efficient data scanning across nodes.

• Incorporate logging and monitoring to track a...read more

I challenged a product requirement due to technical feasibility, ensuring alignment with user needs and project goals.

• Identified a requirement that was technically infeasible within the project timeline.

• Conducted a thorough analysis of the existing architecture to highlight limitations.

• Proposed an alternative solution that met user needs without compromising quality.

• Communicated my concerns to the product team in a con...read more

I have extensive experience with Terraform for infrastructure deployment, focusing on automation and scalability.

• Utilized Terraform to provision AWS resources, including EC2 instances and RDS databases.

• Implemented Infrastructure as Code (IaC) to ensure consistent environments across development and production.

• Created reusable Terraform modules to standardize deployments and reduce redundancy.

• Managed state files using T...read more

I utilize ELK stack and Prometheus + Grafana for log aggregation and alerting, focusing on minimizing alert fatigue.

• Use ELK stack (Elasticsearch, Logstash, Kibana) for centralized logging and visualization.

• Implement Prometheus for metrics collection and Grafana for dashboarding.

• Set up alert thresholds based on historical data to avoid unnecessary alerts.

• Utilize alert grouping and deduplication to reduce noise.

• Incorpora...read more

Investigate service latency by analyzing logs, metrics, and infrastructure to identify bottlenecks and resolve issues.

• Check application logs for errors or warnings that may indicate issues with the new deployment.

• Analyze performance metrics (CPU, memory, I/O) to identify resource bottlenecks.

• Use APM tools (like New Relic or Datadog) to trace requests and pinpoint slow components.

• Review recent changes in the deployment ...read more

React Reconciliation is the process of updating the UI efficiently by comparing virtual DOM trees.

• React uses a virtual DOM to minimize direct manipulation of the real DOM, which is slow.

• When a component's state or props change, React creates a new virtual DOM tree.

• React compares the new virtual DOM with the previous one using a diffing algorithm.

• If differences are found, React updates only the changed parts of the real...read more

API versioning in RESTful backends ensures compatibility and smooth transitions between different API versions.

• Use URI versioning: e.g., /api/v1/resource and /api/v2/resource.

• Implement query parameter versioning: e.g., /api/resource?version=1.

• Utilize header versioning: clients specify the version in request headers.

• Maintain backward compatibility to avoid breaking changes for existing clients.

• Document each version clea...read more

Deploying a full stack app involves setting up the environment, configuring settings, and pushing code to Heroku or Vercel.

• 1. Prepare your app: Ensure your app is production-ready, with necessary configurations for both frontend and backend.

• 2. Create a Heroku/Vercel account: Sign up and log in to your account on the respective platform.

• 3. Install CLI tools: For Heroku, install the Heroku CLI; for Vercel, install the Ve...read more