issue_comments: 897588624

I think I ran into an issue that's perhaps related with extract()

I have a case where I want to create a lookup table for all the related title data where there are possibly multiple null values in the related columns .... ```python3 sql = """\ INSERT INTO "circulation_info" ("item_id", "bib_title", "bib_creator", "bib_format", "bib_pub_year", "checkout_date") VALUES (1, "title one", "creator one", "Book", 2018, "2021-08-12 00:01"), (2, "title two", "creator one", "Book", 2019, "2021-08-12 00:02"), (3, "title three", NULL, "DVD", 2020, "2021-08-12 00:03"), (4, "title four", NULL, "DVD", NULL, "2021-08-12 00:04"), (5, "title five", NULL, "DVD", NULL, "2021-08-12 00:05") """

with sqlite3.connect('test_bib.db') as con: con.execute(sql) ```

when I run the extract() method ...

```python3 db["circulation_info"].extract( [ "bib_title", "bib_creator", "bib_format"
], table="bib_info", fk_column="bib_info_id" )

db = sqlite_utils.Database("test_bib.db")

for row in db["circulation_info"].rows: print(row)

print("\n---\n")

for row in db["bib_info"].rows: print(row) ```

results in this .. ``` {'id': 1, 'item_id': 1, 'bib_info_id': 1, 'bib_pub_year': 2018, 'checkout_date': '2021-08-12 00:01'} {'id': 2, 'item_id': 2, 'bib_info_id': 2, 'bib_pub_year': 2019, 'checkout_date': '2021-08-12 00:02'} {'id': 3, 'item_id': 3, 'bib_info_id': None, 'bib_pub_year': 2020, 'checkout_date': '2021-08-12 00:03'} {'id': 4, 'item_id': 4, 'bib_info_id': None, 'bib_pub_year': None, 'checkout_date': '2021-08-12 00:04'} {'id': 5, 'item_id': 5, 'bib_info_id': None, 'bib_pub_year': None, 'checkout_date': '2021-08-12 00:05'}

{'id': 1, 'bib_title': 'title one', 'bib_creator': 'creator one', 'bib_format': 'Book'} {'id': 2, 'bib_title': 'title two', 'bib_creator': 'creator one', 'bib_format': 'Book'} {'id': 3, 'bib_title': 'title three', 'bib_creator': None, 'bib_format': 'DVD'} {'id': 4, 'bib_title': 'title four', 'bib_creator': None, 'bib_format': 'DVD'} {'id': 5, 'bib_title': 'title five', 'bib_creator': None, 'bib_format': 'DVD'} ```

Seems like it's correctly generating the row data for those lookups, but it's not correctly updating the foreign key back to the primary table? Looks like it just results in a NULL value in that original table.

Any ideas on why? Thanks again!