# Stamp rows with load metadata

Shape / columns

A variant of [Add a calculated column](https://meridian.online/operations/add-a-calculated-column).

Add columns recording where and when each row was loaded, such as a timestamp, source file, batch id or change kind.

Page: <https://meridian.online/operations/add-a-calculated-column/stamp-rows-with-load-metadata>

## Status

Runs as a SQL step.

arcform carries it as a `sql:` step today.

## The DuckDB step

stamp rows with when, where and in which batch they were loaded

It reads the `orders` table the proofs share. Create it first:

```sql
CREATE TABLE orders AS SELECT * FROM (VALUES
  (1,  'Alice Ng',      'north', DATE '2026-01-03', 120.00, 'widget', 'a|b',   '{"channel":"web","items":[1,2]}'),
  (2,  'alice ng',      'north', DATE '2026-01-05',  80.50, 'gadget', 'b',     '{"channel":"shop","items":[3]}'),
  (3,  'Bob  Okafor',   'south', DATE '2026-01-05', 300.00, 'widget', 'a|c',   '{"channel":"web","items":[4,5,6]}'),
  (4,  'Carla Díaz',    'east',  DATE '2026-01-09',  NULL,  'gizmo',  NULL,    '{"channel":"web","items":[]}'),
  (5,  'Bob Okafor',    'south', DATE '2026-01-12',  45.25, 'gadget', 'c',     '{"channel":"phone","items":[7]}'),
  (6,  'Dev Patel',     'west',  DATE '2026-01-12', 510.00, 'widget', 'a',     '{"channel":"web","items":[8,9]}'),
  (7,  'Carla Diaz',    'east',  DATE '2026-01-20',  99.99, 'gizmo',  'b|c',   '{"channel":"shop","items":[10]}'),
  (8,  'Dev Patel',     'west',  DATE '2026-02-02', 510.00, 'widget', 'a',     '{"channel":"web","items":[8,9]}'),
  (9,  'Eve Larsen',    NULL,    DATE '2026-02-03',  15.00, 'gadget', NULL,    '{"channel":"web","items":[11]}'),
  (10, 'Alice Ng',      'north', DATE '2026-02-10', 220.00, 'gizmo',  'a|b|c', '{"channel":"phone","items":[12,13]}')
) t(order_id, customer, region, order_date, amount, product, tags, meta);
```

Then run the statement:

```sql
COPY orders TO '<your_scratch_dir>/orders.csv' (HEADER);
CREATE TEMP TABLE result AS
SELECT order_id, now() AS loaded_at, parse_filename(filename) AS source_file, 'batch-001' AS batch_id, 'insert' AS change_kind
FROM read_csv('<your_scratch_dir>/orders.csv', filename = true);
SELECT order_id, loaded_at IS NOT NULL AS stamped, source_file, batch_id, change_kind FROM result ORDER BY order_id LIMIT 3;
SELECT CASE WHEN ((SELECT count(*) = 10 AND count(DISTINCT loaded_at) = 1 AND min(loaded_at) IS NOT NULL AND min(source_file) = 'orders.csv' AND max(source_file) = 'orders.csv' AND min(batch_id) = 'batch-001' AND max(change_kind) = 'insert' FROM result)) THEN 'as expected' ELSE error('each of the ten rows was not stamped with one load time, orders.csv, batch-001 and insert') END AS verdict;
```

Replace `<your_scratch_dir>` with a directory of your own that you can write to before running the statement.

The statement writes `orders.csv` itself, in `<your_scratch_dir>`.

It needs nothing installed beyond DuckDB itself.

## What other tools call it

Meridian's classification; an independent blind rating agreed on 95.7% of 324 rows (variant, version 3).

- Duckle: [`Audit Stamp`](https://github.com/slothflowlabs/duckle/blob/f85f8960edfb6efbf4cb89d58a7b32e16df0e867/website/docs/components.html) (read 2026-09-25)
- AWS Glue: [`Add Current Timestamp`](https://docs.aws.amazon.com/glue/latest/dg/transforms-add-current-timestamp.html) (read 2026-09-27)
- Apache SeaTunnel: [`Metadata`](https://seatunnel.apache.org/docs/2.3.13/transforms/metadata) (read 2026-09-27)
- Apache SeaTunnel: [`RowKindExtractor`](https://seatunnel.apache.org/docs/2.3.13/transforms/rowkind-extractor) (read 2026-09-27)
- Trifacta: [`filepath`](https://help.alteryx.com/aac/en/trifacta-classic/reference/transformation-reference.html) (read 2026-09-27)
- VisiData: [`addcol-audiometadata`](https://github.com/saulpw/visidata/blob/7609212ec2febafa9caba7183cbebfaf49627909/visidata/features/addcol_audiometadata.py#L39) (read 2026-09-23)