要打开 MS Access 数据库保护密码，您需要更改连接字符串

To open an MS Access database protect with password you need to change your connection string

"Provider=Microsoft.ACE.OLEDB.12.0;" + 
"Data Source=C:\Users\Pasindu\Documents\database9.accdb;" + 
"Jet OLEDB:Database Password=MyDbPassword;"

其中 MyDbPassword 应替换为正确的字符串

where MyDbPassword should be replaced with the correct string

对于您问题的删除部分，我将尝试更改

For the delete part of your question, I will try to change the command in

delete * from Table1 where [Student number]=@sno

如果您的字段名称包含空格，则将名称用方括号括起来

If your field name contains spaces then encapsulate the name with square brackets