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Home/Questions/Cloud/Tools/How do you merge data from different sources in ADF while maintaining data quality?

How do you merge data from different sources in ADF while maintaining data quality?

Cloud/Toolsmedium0.3 min readPremium

Architectural approach: Data Flow or Lookup + Join. Quality: (1) Validation—filter nulls, invalid ranges. (2) Deduplication—Surrogate Key, Window. (3) Conform types. (4) Error handling—reject table for bad rows. Flow: Multiple sources → Join → Filter invalid → Dedupe → Sink....

🤖 Analyze Your Answer
Frequency
Low
Asked at 1 company
Category
179
questions in Cloud/Tools
Difficulty Split
104E|27M|48H
in this category
Total Bank
1,863
across 7 categories
Asked at these companies
Virtusa
Key Concepts Tested
joinwindow

Why This Question Matters

This medium-level Cloud/Tools question appears frequently in data engineering interviews at companies like Virtusa. While less common, it tests deeper understanding that distinguishes strong candidates. Mastering the underlying concepts (join, window) will help you answer variations of this question confidently.

How to Approach This

Break this problem into components. Identify the core trade-offs involved, then walk the interviewer through your reasoning step by step. Demonstrate awareness of edge cases and production considerations - this is what separates good answers from great ones.

Expert Answer
52 words

Architectural approach: Data Flow or Lookup + Join. Quality: (1) Validation—filter nulls, invalid ranges. (2) Deduplication—Surrogate Key, Window. (3) Conform types. (4) Error handling—reject table for bad rows. Flow: Multiple sources → Join → Filter invalid → Dedupe → Sink. Best practice: Define quality rules; reject table; log metrics; validate before merge.

The complete answer continues with detailed implementation patterns, architectural trade-offs, and production-grade considerations covering performance optimization and real-world examples.

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According to DataEngPrep.tech, this is one of the most frequently asked Cloud/Tools interview questions, reported at 1 company. DataEngPrep.tech maintains a curated database of 1,863+ real data engineering interview questions across 7 categories, verified by industry professionals.

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