python - 错误 : trying to redefine a primary key as non-primary key

Question

我正在使用 dataset尝试将 postgres 数据库备份到 sqlite 文件中的库。我正在运行的代码如下:

local_db = "sqlite:///backup_file.db"

with dataset.connect(local_db) as save_to:
    with dataset.connect(postgres_db) as download_from:

        for row in download_from['outlook']:
            save_to['outlook'].insert(row)

如果我打印表格的一行，它看起来像这样:

OrderedDict([
    ('id', 4400),
    ('first_sighting', '2014-08-31'),
    ('route', None),
    ('sighted_by', None),
    ('date', None)
])

但是，当我到达 save_to['outlook'].insert(row) 行时，我收到以下堆栈跟踪错误:

Traceback (most recent call last):
  File "/home/anton/Development/Python/TTC/backup_db.py", line 25, in <module>
    save_to['outlook'].insert(dict(row))
  File "/home/anton/.virtualenvs/flexity/lib/python3.6/site-packages/dataset/table.py", line 79, in insert
    row = self._sync_columns(row, ensure, types=types)
  File "/home/anton/.virtualenvs/flexity/lib/python3.6/site-packages/dataset/table.py", line 278, in _sync_columns
    self._sync_table(sync_columns)
  File "/home/anton/.virtualenvs/flexity/lib/python3.6/site-packages/dataset/table.py", line 245, in _sync_table
    self._table.append_column(column)
  File "/home/anton/.virtualenvs/flexity/lib/python3.6/site-packages/sqlalchemy/sql/schema.py", line 681, in append_column
    column._set_parent_with_dispatch(self)
  File "/home/anton/.virtualenvs/flexity/lib/python3.6/site-packages/sqlalchemy/sql/base.py", line 431, in _set_parent_with_dispatch
    self._set_parent(parent)
  File "/home/anton/.virtualenvs/flexity/lib/python3.6/site-packages/sqlalchemy/sql/schema.py", line 1344, in _set_parent
    self.key, table.fullname))
sqlalchemy.exc.ArgumentError: Trying to redefine primary-key column 'id' as a non-primary-key column on table 'outlook'

关于我做错了什么有什么想法吗？我在 python 2.7.14 和 3.6.3 中试过这个

Answer 1

假设你有一个为“outlook”制作的模式和表格，你是否制作了一个PK字段？有没有让sqlite决定哪个字段做PK字段？

您尝试插入 id 两次是非常重要的。有一次，sqlite是自己插入的，其他的来自其他表记录。