A flat row: one property for each field to set, keyed by field key. Text and date fields take a string (an ISO 8601 date), number fields a number and boolean fields a boolean. Select fields take an option label or ID, or an array of them; a string with labels joined by ", " also works, as rows from this API show them. When two options have the same label, send the option ID. User fields take user IDs, and linked entity fields take entity IDs, as a comma-separated string or an array. null clears a cell. Relation fields are set with the linkRecords GraphQL mutation, and computed fields (rollup, lookup, formula) cannot be set. A row read from this API can be changed and sent back: properties that start with _ are ignored, and so are relation and computed fields that are null or unchanged.