Dennis Lewis

Results-driven Data Engineer with 4.5 years of experience at TCS building scalable ETL/ELT pipelines using Azure Databricks, Azure Data Factory, Azure Key Vault, Azure Data Lake, SQL Server and PySpark, SQL, Python, SparkSQL. Expertise in data ingestion, transformation, and orchestration across Life Sciences and Manufacturing domains. Databricks and Microsoft Certified with a strong record of delivering high-quality, production-grade data solutions and BI integrations.

Data Engineer at Tata Consultancy Services (TCS) (2021-12 – Present)

Clients: Bayer Inc, Ecolab Inc

• Designed and developed end-to-end ETL/ELT pipelines on Azure Databricks, ingesting data from SAP, Azure Blob Storage, and relational databases into curated data layers for Life Sciences and Manufacturing clients.
• Built and automated Databricks Workflows for scheduling and orchestration of large-scale batch data processing jobs, improving pipeline reliability and reducing manual intervention.
• Managed Azure Data Factory (ADF) and Azure Databricks (PySpark) transformation pipelines, Medallion Architecture across Bronze, Silver, and Gold layers in Azure Data Lake Store (ADLS), enabling efficient processing and analytics for downstream reporting and client platforms.
• Implemented Data Governance and security policies using Unity Catalog and Azure Key Vault, including access controls, audit logging, and compliance standards to ensure secure handling of sensitive financial datasets.
• Developed optimized PySpark and Spark SQL and complex SQL transformations on datasets of millions of records, enabling accurate BI reporting and business analytics for downstream consumers.
• Managed end-to-end CI/CD pipelines using GitHub Actions and Azure DevOps to automate the deployment of notebooks, jobs, and workflows across development and production environments.
• Developed Data Quality frameworks including schema validation, row-count reconciliation, duplicate detection, and business-rule validation ensuring 98-99% data accuracy and reliability.
• Managed production monitoring and incident resolution via ServiceNow; authored team knowledge base with SOPs, error guides, and best practices, ensuring seamless business continuity. Handled P2–P4 production incidents, performed Root Cause Analysis (RCA), and ensured SLA-driven resolution for critical data pipeline failures.

Bachelor of Technology (B.TECH) – Durg, Chhattisgarh (2020)