primary_key as only column on sqlite
force_insert=True
The logging helped a ton--didn't find that till I looked at https://github.com/coleifer/peewee/issues/961 but super helpful.

Thx.

Hey there--great library, btw.

I'm running into a couple of issues (working directly on head/master):
1. A table with only a primary key as the sole field:

class SimpleTest(BaseModel):
  name = CharField(primary_key=True)

When I call:
  simple = SimpleTest(name="Charlie")
  print("Saving %d simples" % simple.save())

I get:

  File "./peewee/peewee.py", line 4862, in save
    rows = self.update(*_field_dict).where(self._pk_expr()).execute()
  File "./peewee/peewee.py", line 3224, in execute
    return self.database.rows_affected(self._execute())
  File "./peewee/peewee.py", line 2748, in _execute
    return self.database.execute_sql(sql, params, self.require_commit)
  File "./peewee/peewee.py", line 3599, in execute_sql
    self.commit()
  File "./peewee/peewee.py", line 3423, in __exit__
    reraise(new_type, new_type(_exc_args), traceback)
  File "./peewee/peewee.py", line 132, in reraise
    raise value.with_traceback(tb)
  File "./peewee/peewee.py", line 3592, in execute_sql
    cursor.execute(sql, params or ())
peewee.OperationalError: near "WHERE": syntax error
