Objective and core distinction
A file format describes how information is encoded and organized. A data store supplies a place and interfaces for keeping and using it. CSV offers delimited text, JSON hierarchical objects and collections, Parquet columnar organization, and Avro row-based records. These are useful distinctions, not a ranking from worst to best. A human-readable export may suit an exchange contract while an analytical process benefits from a different physical layout. A relational database can offer typed records and query/update operations. Do not confuse a query result exported into a file with an ongoing database operation. State whether the task is an exchange, a retained source collection, or access to current records before choosing an approach.
Worked example
Fictional case:a small observatory receives a nightly fixed-column measurement export and also keeps richer equipment-description documents. Its spreadsheet users need to inspect the export directly; an analytical reader repeatedly scans a few measurement columns across many nights. Keep those reader requirements separate. A CSV can meet the human-readable fixed-column exchange. A Parquet representation may provide the columnar layout wanted by the analytical reader; that does not prove a measured speed improvement without a workload check. The equipment document can preserve nested properties independently. A conversion should record what it preserves rather than assume every convenient target format retains the original organization.
Changed condition and misconception
Suppose the observatory now needs versioned, transactional updates to an analytical table over Parquet files. That is a new requirement. Delta Lake adds a transaction log and table semantics over Parquet; the format’s column layout alone is not a table-level transaction history. Likewise, a cache, partition directory or extra file copy can help another requirement without supplying the same mechanism. On the operational side, a SELECT retrieves a result and an UPDATE changes matching stored rows. Exporting a fresh result does not retroactively change the source records. These distinctions connect format, service and operation without pretending they are interchangeable.
Transfer check
Transfer task:a charity publishes a monthly CSV report but must also maintain the current contact status of individual volunteers throughout the month. A colleague says the old CSV is the current database because it contains the same column names. What information is missing? Check basis:the update and synchronization contract. A snapshot can reflect a past result without incorporating later changes. Ask where the authoritative current record is stored, which operations change it, and how a later export is produced. The correct next step is to clarify those roles rather than choose a product solely from the file extension. Then complete the linked format and operation tasks.
Try it, then explain it.
Complete a short set without looking at the example. After each answer, explain which evidence or rule supports your decision and why the alternatives do not fit.
Sources & authorship
Original OpenExam explanations and examples. References support the concepts; they are not the source of copied questions. Independent educator review is pending.
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