The sqlite3 docs say that lastrowid is set to None after executemany(), or after execute()'ing statements that are not INSERTs or REPLACEs. This is not true; in those cases, lastrowid is preserved. lastrowid is only None in a pristine cursor. Suggesting to reword the docs so they harmonise with the implementation.

Note, there is a quirk, or bug with lastrowid: it is set to 0 if the first statement that's execute()d on a cursor is a non-INSERT/REPLACE statement. For example:

    >>> import sqlite3
    >>> cx = sqlite3.connect(":memory:")
    >>> cu = cx.cursor()
    >>> cu.lastrowid
    >>> cu.execute("select 1")
    >>> cu.lastrowid
    0

This behaviour is consistent across current main through 3.7 (though in 2.7, the behaviour is consistent with the docs, so it probably changed a long time ago). I'm not sure it's worth noting this side effect in the docs though.

Oh, and the docs says that lastrowid "provides the rowid of the last modified row". This is not true; it provides the row id of the last _inserted_ row.

I also suggest to add a note about tables without rowids, quoting the SQLite docs:

    Inserts into WITHOUT ROWID tables are not recorded.

FYI: https://sqlite.org/c3ref/last_insert_rowid.html

New changeset b6aa38f1ca79600f2ab46ac114ff36461a19c4a3 by Erlend Egeberg Aasland in branch 'main':
bpo-46261: Update `sqlite3.Cursor.lastrowid` docs (GH-30407)
https://github.com/python/cpython/commit/b6aa38f1ca79600f2ab46ac114ff36461a19c4a3

New changeset 987fba102e909229dd2aa1a6115aa28d514c1818 by Miss Islington (bot) in branch '3.10':
bpo-46261: Update `sqlite3.Cursor.lastrowid` docs (GH-30407)
https://github.com/python/cpython/commit/987fba102e909229dd2aa1a6115aa28d514c1818

New changeset b29aa71090e4dd34900660ecca8bb62667440f41 by Miss Islington (bot) in branch '3.9':
[3.9] bpo-46261: Update `sqlite3.Cursor.lastrowid` docs (GH-30407)
https://github.com/python/cpython/commit/b29aa71090e4dd34900660ecca8bb62667440f41

Thanks for this, Erlend!