Customer Data Integration interview questions

Undocumented schemas, restricted access, no staging environment, and data that disagrees with what you were told.

3 questions in Forward Deployed Engineering.

Forward Deployed EngineeringA 21-minute read on how the topic fits together, before the questions.Forward deployed engineering fundamentals57 short answers on one page, for revising rather than studying.

hard3

hardScenarioDesignCoding

You have read access to the customer's production database and there is no staging environment. How do you develop and test without putting their system at risk?

Pull a bounded, representative extract into an environment you control and develop against that, keeping production for read-only verification under agreed limits, and treat every write path as something proven against a restored copy before it runs anywhere near live.

6 minmid, senior, staff

hardScenarioCodingCase Study

The customer's schema has no documentation and the person who designed it has left. How do you work out what the tables actually mean?

Read the data rather than the DDL: profile every column for cardinality, null rate and value distribution, use foreign-key-shaped joins to test relationships you suspect, and confirm each conclusion against a report the business already trusts before you build on it.

6 minmid, senior, staff

hardScenarioCodingCase Study

The business told you a field is always populated, and in production it is null for a third of the rows. How do you work out what is going on and what do you do about it?

Segment the nulls before drawing any conclusion — by date, source system, record type and creating process — because a null rate that clusters is a documented business path nobody mentioned, while one spread evenly is usually a genuine capture defect.

7 minmid, senior, staff