vb.net - 连接mysql数据库修改密码

Question

“adapter = New MySqlDataAdapter("UPDATE user SET Password WHERE Password ='" & txtpassword.Text & "'") 行中有错误

我该如何解决？

Private Sub getdbdata()

    Try
        mysqlconn = New MySqlConnection("server=localhost;username=root;database=bank")

        dataset = New DataSet
        adapter = New MySqlDataAdapter("UPDATE user SET Password WHERE Password ='" & txtpassword.Text & "'")
        adapter.Fill(dataset, "user")

        mysqlconn.Open()

        reader = command.ExecuteReader

        If reader.HasRows Then
            Form1.Show()
            Me.Visible = False

        Else
            MessageBox.Show("Password change unsuccessful.")
        End If


        reader.Close()
        mysqlconn.Close()

    Catch ex As MySqlException
        MessageBox.Show(ex.Message)

    End Try

End Sub

Answer 1

主要问题在于更新查询的语法。

所以在你的代码中做这个改变：

    dataset = New DataSet
    adapter = New MySqlDataAdapter("UPDATE user SET Password = '" & txtNewpassword.Text & "' " & _
                                   "WHERE userName = '" & txtuser.Text & "' and " & _
                                   "Password ='" & txtOldpassword.Text & "'")
    adapter.Fill(dataset, "user")

现在代码的含义是完整的，它将重置密码为 txtNewpassword 中的用户名txtuser和匹配密码的用户txtOldpassword

Answer 2

Imports MySql.Data.MySqlClient
Public Class Settings
    Dim con As New MySqlConnection("host =localhost;user id=root;password=;database=cidb")
    Dim cmd As New MySqlCommand
    Dim dr As MySqlDataReader
    Private Sub Button1_Click_1(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        con.Open()
        cmd.Connection = con
        cmd.CommandText = "select * from usertbl where uname='" & user.Text & "'and upassword= '" & Pword.Text & "'"

        dr = cmd.ExecuteReader
        If dr.HasRows Then
            Settings()
        Else
            MsgBox("Invalid Username or Password!")
        End If

    End Sub

 Private Sub Settings()
        Dim con As New MySqlConnection("host =localhost;user id=root;password=;database=cidb")
        Dim cmd As New MySqlCommand
        con.Open()
        cmd.Connection = con
        cmd.CommandText = "update usertbl set upassword='" & NewPword.Text & "' where uname= '" & usertxt.Text & "'"
        cmd.ExecuteNonQuery()
            MsgBox("You're successfully change your Password!")
            usertxt.Text = " "
            Pwordtxt.Text = " "
            Newuser.Text = " "
           con.Close()
    End Sub