Rowexpander requires key to be set in return dict

[fromm1990]

When using the key as part of the lookupatts, the rowexpander expects the key column to be included in the return dict.
If the key is not included, duplicate rows will be created. Having keys as part of the lookupatts is not uncommen in a smartkey usecase.

The following code results in incrementing date_ids:

CREATE TABLE date_dim(
    date_id    INT         PRIMARY KEY,
    year_no    SMALLINT    NOT NULL,
    month_no   SMALLINT    NOT NULL,
    day_no     SMALLINT    NOT NULL,
    week_no    SMALLINT    NOT NULL,
    weekday_no SMALLINT    NOT NULL,
    quarter_no SMALLINT    NOT NULL,
    iso_date   VARCHAR(10) NOT NULL,
    month_name VARCHAR(9)  NOT NULL
);

from pygrametl import ConnectionWrapper
from typing import Any
from datetime import datetime
from pygrametl.tables import CachedDimension

cw = ConnectionWrapper(...)
key = "date_id"

def expand(row: dict[str, Any], name_map: dict[str, str]):
    col = name_map.get(key, key)
    date_key = row[col]
    dt = datetime.strptime(str(date_key), "%Y%m%d")
    calendar = dt.isocalendar()
    return {
        "year_no": dt.year,
        "month_no": dt.month,
        "day_no": dt.day,
        "quarter_no": (dt.month // 4) + 1,
        "iso_date": dt.strftime("%Y-%m-%d"),
        "month_name": dt.strftime("%B"),
        "week_no": calendar.week,
        "weekday_no": calendar.weekday,
    }


dim = CachedDimension(
    name="date_dim",
    key=key,
    attributes=[
        "year_no",
        "month_no",
        "day_no",
        "week_no",
        "weekday_no",
        "quarter_no",
        "iso_date",
        "month_name",
    ],
    lookupatts=[key],
    targetconnection=cw,
    rowexpander=expand,
)

rows = [
    {"date_id": 20241001},
    {"date_id": 20241001},
    {"date_id": 20241001},
    {"date_id": 20241001},
    {"date_id": 20241001},
]


for row in rows:
    dim.ensure(row)