python - 插入 SQLite 数据库的行数为负数

Question

我正在尝试通过 Python 代码将新记录插入到 SQLite 数据库中。

  con = sqlite.connect(connectionString)
  cur = con.cursor()
  countOfNewItems = 0
  for ...
    try:
      con.execute("insert or ignore into items ...")
      countOfNewItems += cur.rowcount
    except:
      cur.close()
      con.close()
      print "Error when inserting item '%s' to database." % item
      exit(1)
  cur.close()
  con.commit()
  con.close()
  print "%d new items have been inserted." % countOfNewItems

我的代码报告插入记录的负数 (-5141)。

因为我的数据库是空的，所以我可以通过命令行找出插入了多少条记录

从项目中选择 count(*);

4866

你能告诉我哪里出了问题吗？为什么这两个值不匹配，为什么是负数？

Answer 1

http://docs.python.org/library/sqlite3.html#sqlite3.Cursor.rowcount

Although the Cursor class of the sqlite3 module implements this attribute, the database engine’s own support for the determination of “rows affected”/”rows selected” is quirky.

和

As required by the Python DB API Spec, the rowcount attribute “is -1 in case no executeXX() has been performed on the cursor or the rowcount of the last operation is not determinable by the interface”.