Convert Primary Key Finder Online
Find unique identifiers, composite keys, and almost-keys that fail due to blanks or duplicates. Use Primary Key Finder in your browser with no signup, no daily limit, and no backend processing for tool input.
Problem
You need to move data through Primary Key Finder without writing a script or uploading the source file to another service.
What to do
Primary Key Finder is useful when a format mismatch blocks the next step. Convert the data, inspect the preview, then continue into validation, cleanup, or export.
- 1Paste or upload the source data into Primary Key Finder.
- 2Confirm the format options and preview the result.
- 3Copy or download the converted output.
Use the browser tool
Primary Key Finder examines a CSV and reports which columns could actually serve as a primary key: single columns that are unique and complete, composite combinations that become unique together, and — most usefully — the near-misses, columns that would be a key except for a handful of blanks or a couple of duplicate values. Those almost-keys are usually the interesting finding, because they point at a data quality problem rather than a modelling one.
People also ask
- What is an almost-key?
- A column that would be a valid key except for a small number of blanks or duplicates — often fewer than five rows in a large file. It usually indicates a data quality issue in those rows rather than a genuinely unsuitable column.
- Why can't a primary key contain nulls?
- A key has to identify a row unambiguously, and a null means "unknown" — two unknown values cannot be shown to be different, so uniqueness cannot be guaranteed. Databases enforce this by rejecting the constraint.
- How many columns does it try for composite keys?
- It tests combinations up to a practical limit; beyond a few columns the number of combinations grows too fast to be useful, and a key that wide is usually a sign the table needs restructuring.