Flattening Nested and Repeated XML Elements to CSV

Flattening XML to CSV works cleanly when each record is a flat list of simple fields — but nested child elements need dot-notated column names, and repeated elements within a single record (like multiple <tag> elements inside one <product>) have to be joined into a single cell, since a CSV cell can't hold more than one value.

Nested elements: dot notation, same as JSON

<product><name>Widget</name><price><amount>19.99</amount><currency>USD</currency></price></product> flattens into three columns: name, price.amount, and price.currency — the same dot-notation convention used for nested JSON, since both are solving the identical problem of representing hierarchy in a flat grid.

Repeated elements within one record: the harder case

If a single <product> contains multiple <tag> elements, there's no clean column-per-tag answer unless every record has exactly the same number of tags — a converter typically joins them into one cell ("electronics; sale; new"), which is readable but means that cell's individual values aren't directly queryable as separate columns without re-splitting the string later.

Records with inconsistent fields

If some records include an optional element that others omit, a correct converter needs a column for every field seen across the entire document — with blank cells for records missing it. A naive converter that only looks at the first record's structure will silently misalign every column starting at the first record where the pattern differs.