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Data Engineer Junior Interview Questions

390 verified Data Engineer Junior interview questions — solve with answers, learn from explanations, test yourself in a real simulation.

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Sample questions

Data Governance LineageDifficulty 1
In the context of a data platform, what best describes 'data lineage'?
  • aThe physical storage location where a dataset's files are kept on disk
  • bA traceable record of data's origin and transformations downstream
  • cA naming convention applied to tables and columns
  • dThe access permissions assigned to a dataset's owner
Explanation:Data lineage is the record of where data originates and how it's transformed on its way to consumption; it is not a backup schedule, naming convention, or permission list.
Data Governance LineageDifficulty 2
A dashboard metric suddenly shows an unexpected drop. Before touching any code, what is the most useful first step that lineage information enables?
  • aIncreasing the retry count of the job that produces the dashboard
  • bAsking the dashboard's end users to describe what they expected to see
  • cRestarting the entire data platform to clear any cached state
  • dTracing the metric backward through lineage to the changed source
Explanation:Lineage lets an engineer trace the metric backward to the exact upstream source or transformation that changed, instead of guessing via retries or restarts.
Data Governance LineageDifficulty 1
Which statement about data lineage is accurate?
  • aLineage can be captured at different levels, e.g. table or column
  • bLineage only matters for data stored in spreadsheets
  • cLineage is generated once and never needs to be updated
  • dLineage information is identical to a database's index structure
Explanation:Lineage can be captured at different granularities, from whole tables down to individual columns, depending on the need.
Data Governance LineageDifficulty 2
A team plans to drop a column from a shared table. What should they check first to avoid breaking anything?
  • aWhether the column name is spelled consistently across the codebase
  • bHow much disk space the column currently occupies
  • cThe lineage graph, to see which downstream consumers use it
  • dThe color scheme used in dashboards that display the table
Explanation:The lineage graph shows exactly which downstream reports and pipelines depend on that column, so the team can assess the real impact before dropping it.
Data Governance LineageDifficulty 2
Why is column-level lineage generally more useful than table-level lineage for impact analysis?
  • aIt requires less metadata to maintain overall
  • bIt shows exactly which downstream fields depend on that column
  • cIt automatically fixes broken pipelines without manual intervention
  • dIt removes the need for a data catalog entirely
Explanation:Column-level lineage pinpoints which specific downstream fields are affected, avoiding wasted effort investigating unrelated parts of a table.
Data Governance LineageDifficulty 2
Before renaming a widely-used table, an engineer wants to know exactly which reports would break. Lineage tracking helps by...
  • aAutomatically renaming the table in every downstream system
  • bNotifying all employees in the company by broadcast email
  • cEncrypting the table so unauthorized changes are prevented
  • dListing every downstream consumer of that table
Explanation:Lineage tracking lists every downstream consumer of a table, so each one can be reviewed or updated before a breaking change like a rename.

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