连接到mysql并减少字段 [英] Connecting to mysql and decreasing a field

问题描述

嘿，所有iam都使用vb.net 2010，我想使字段减少1，每次使用这里都是我的代码，但是它不起作用，请帮助

hey all iam using vb.net 2010 and i want to make a field decreased by 1 each use here is my code but it''s not working please help

Imports MySql.Data.MySqlClient

Public Class Form1
    Private connStr As String = "Database=huawiunlocking;" & _
                    "Data Source=********;" & _
                    "User Id=**********;Password=*********;" & _
                    "Connection Timeout=20"

    Private Sub Form1_Load(ByVal sender As System.Object, _
            ByVal e As System.EventArgs) Handles MyBase.Load
        Console.WriteLine(updateRecord("UPDATE Users SET Username=''Admin'' WHERE Credits =''10''"))
    End Sub
    Function updateRecord(ByVal query As String) As Integer
        Try
            Dim rowsEffected As Integer = 0
            Dim connection As New MySqlConnection(connStr)
            Dim cmd As New MySqlCommand(query, connection)

            connection.Open()

            rowsEffected = cmd.ExecuteNonQuery()

            connection.Close()

            Return rowsEffected
        Catch ex As Exception
            Console.WriteLine(ex.Message)
        End Try
    End Function

End Class

在此先感谢

Thanks in advance

推荐答案

您为什么希望该代码将字段减少任何数量:

Why would you expect that code to reduce a field by any amount:

UPDATE Users SET Username='Admin' WHERE Credits ='10'

所有操作都将用户"表中所有记录的用户名"设置为管理员".当前信用"为10.

完全不会更改任何数值.

All that does is set the "Username" of all records in the "Users" table which currently have a "Credits" of 10 to "Admin".

No numeric values are altered at all.

UPDATE Users SET Credits=Credits-1

前提是贷方不是字符串(如您的示例所示).

或者让我们进一步了解正在使用的数据结构以及您要更新的字段.

provided that Credits is not a string as shown in your sample.

Or let us know more about the data structure being used and which field you want to update.

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