VB.NET添加新记录问题 [英] VB.NET add new record problem

问题描述

我目前正在处理一个需要用户登录的应用程序。作为此登录过程的一部分，登录时间和日期的详细信息存储在Access DB中。



我使用以下代码来实现此目的，但它只有覆盖表中的第一条记录，每次有人登录时都不会添加新记录。有人指向正确的方向可以让它工作吗？

Hi,
I am currently working on an application that required users to login. As part of this login procedure, details of the time and date of login are stored in an Access DB.

I have used the following code to achieve this, but it only overwrites the first record in the table, it doesn't add a new record each time someone logs in. Could someone point in in the right direction to get this to work?

strSQL = "INSERT INTO tbl_login_history(username, login_date, login_time) VALUES (@user_real_name, @login_date, @login_time)"
                    cmd = New OleDbCommand(strSQL, objconn)

                    cmd.Parameters.Clear()
                    cmd.Parameters.AddWithValue("@user_real_name", user_real_name)
                    cmd.Parameters.AddWithValue("@login_date", DateTime.Now.ToString("dd/mm/yyyy"))
                    cmd.Parameters.AddWithValue("@login_time", DateTime.Now.ToString("HH:mm"))

                    cmd.ExecuteNonQuery()
                    objconn.Close()
                Catch ex As Exception
                    MsgBox(ex.Message, "Error")
                End Try

推荐答案

插入语句总是插入一个新行问题很可能在其他地方。

几件事要检查：

• ExecuteNonQuery的返回值是多少，受影响的行数是多少？
• 是打开正确访问数据库的连接吗？
• 是项目的访问数据库部分，在编译应用程序时是否会在bin文件夹中被覆盖？
• 您是否有正在进行的交易但是在关闭连接之前没有提交？
• 任何错误？

Insert statement always inserts a new row so the problem is most likely elsewhere.
Few things to check:

• what is the return value of the ExecuteNonQuery, how many rows were affected?
• is the connection opened to the correct access db?
• is the access db part of the project, does it get overwritten in bin folder when the applciation is compiled?
• do you have an on-going transaction but you don't commit before closing the connection?
• any errors?

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