{
    "action": "final",
    "content": "Column classification for `raw.semi_conductor_se` (422,729 rows, 13 columns), based on the column metadata I pulled (types, semantic roles, null counts, distinct counts, ranges):\n\n**Identifiers**\n- `_unnamed_0` (BIGINT): a row index running 0..422728, with about 405k distinct values and no nulls. It is an artifact of the CSV export and has no analytical meaning.\n- `stock_name` (VARCHAR): the ticker symbol, with about 171 distinct values (e.g. `000660.KS`..`XPER`). Together with `date` it forms the grain of the table, one row per stock per trading day.\n\n**Categorical dimensions**\n- `company_name` (VARCHAR): about 149 distinct values (`ACM Research`..`u-blox`), no nulls. It is the main grouping field. There are more tickers (~171) than company names (~149), so some companies appear under more than one ticker, such as multiple listings or exchanges. Check this before grouping by company.\n\n**Numeric metrics (measures)**\n- `open`, `high`, `low`, `close` (DOUBLE): daily prices, all non-null. Values range from about 0.009 to 300,000, which suggests mixed currencies (for example KRW-quoted Korean tickers) and penny-priced stocks. Do not compare raw price levels across companies without normalising.\n- `volume` (BIGINT): shares traded, from 0 to about 3.69 billion, non-null.\n\n**Dates / times**\n- `date` (DATE): the trading day, spanning 2012-01-02 to 2025-08-04, with about 3,295 distinct dates and no nulls. This is the only business time axis.\n- `_ingestion_timestamp` (TIMESTAMP): a single constant value, so it is load metadata and not a business time axis.\n\n**Pipeline / lineage metadata (not analytical)**\n- `_batch_id`, `_source_file`, `_source_system`: each has exactly one distinct value across all rows (the last is `api`). They carry no analytical information and can be ignored.\n\n**Summary:** there are 2 identifiers, 1 categorical dimension, 5 numeric metrics, 1 business date, and 4 constant ingestion-metadata columns (1 timestamp plus 3 text). No column has nulls."
}