there is no connection 'default' on this thread, are you sure you opened it?
时间: 2024-01-06 15:03:26 浏览: 27
This error message typically occurs when you attempt to perform a database operation without first opening a connection to the database.
To fix this, you need to ensure that you have opened a connection to the correct database before executing database operations. You can do this by creating a new instance of the database connection object and specifying the appropriate connection details such as the database name, username, and password.
Here's an example of how to open a connection to a MySQL database using Python:
```
import mysql.connector
# Create a new connection object
cnx = mysql.connector.connect(user='username', password='password',
host='localhost',
database='database_name')
# Perform database operations here...
# Close the connection
cnx.close()
```
Make sure to replace `username`, `password`, `localhost`, and `database_name` with the appropriate values for your database.
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