Table grain and primary-key worksheet ===================================== StatMedAnalysis | Downloadable worksheet | 5 November 2026 Decide what one row represents and validate a candidate key before combining or summarizing records. Working instructions Describe one row in a sentence. Propose the smallest set of columns that identifies it under the collection design. Count null and repeated candidate keys. Inspect repeated keys to see whether they indicate legitimate repeated observations, accidental duplication or an omitted dimension. Working record Save a local copy. Use public, hypothetical or aggregate information. Project code ____________________ Prepared on ____________________ Source and table version ___________________________________________________________________ One-row statement ___________________________________________________________________ Candidate key columns and types ___________________________________________________________________ Null-key count ___________________________________________________________________ Repeated key groups and affected rows ___________________________________________________________________ Legitimate repeat dimension, if any ___________________________________________________________________ Revised design or resolution plan ___________________________________________________________________ Validation rule and retest outcome ___________________________________________________________________ Hypothetical worked case In a fictional laboratory table, specimen plus analyte repeats for technical replicates. Adding replicate number distinguishes those results only if that number is consistently recorded. Averaging duplicates would hide the table’s collection structure. Decision and follow-up Approve a key only when values remain unique and complete at the declared grain and the selected columns carry a defensible identity. A unique row number added after import leaves the original entity identity unresolved. Decision _______________________ Date ___________________________ Evidence retained at _____________________________________________ Next action ____________________ Owner __________________________ Official reference checked 5 November 2026 https://www.w3.org/TR/tabular-data-model/