Help i am using vb.net2010 and trying to access my database through sqlyog but there seems to be an error on con.Open() line.(I'm trying to create a login form with a database and this is my first time)
Public con As New Odbc.OdbcConnection
Private Sub btnlogin_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnlogin.Click
con = New Odbc.OdbcConnection("dsn=cara")
Dim cmd As New Odbc.OdbcCommand
Dim reader As Odbc.OdbcDataReader
cmd.Connection = con
con.Open()
cmd.CommandText = " SELECT username,password FROM userinfo WHERE username='" & txtusername.Text & "' and password='" & txtpassword.Text & "'"
reader = cmd.ExecuteReader
If reader.HasRows Then
Admin_Page.Show()
Else
MessageBox.Show("Invalid Username or Password")
End If
Related
I have 2 forms in my winform application.Form 1 serves as a LogIn form and Form 2 serves as a page that a user would see after log in.Now my form 1 has two text boxes(for username and password) and a button(to login/show form 2).Every time a user runs the application, he has to login using form 1.What i want is, when a user logs in for once,from the next time on,he wouldn't have to log in anymore/he would see the form 2 directly instead of Form 1>Form 2. My code is :
Private Sub Login_Form_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
If My.Settings.UserName = "" Then
Me.Show()
Else
Try
provider = "Provider=Microsoft.ACE.OLEDB.12.0; Data Source="
dataFile = "XXXXXXX"
connString = provider & dataFile
myConnection.ConnectionString = connString
Dim cmd As OleDbCommand = New OleDbCommand("SELECT * FROM [Login] WHERE [user_name] = #username AND [password] = #password", myConnection)
myConnection.Open()
cmd.Parameters.Add("#username", OleDbType.VarChar).Value = My.Settings.UserName
cmd.Parameters.Add("#password", OleDbType.VarChar).Value = My.Settings.Password1
Dim adapter As New OleDbDataAdapter(cmd)
Dim table As New DataTable
adapter.Fill(table)
If table.Rows.Count <= 0 Then
MsgBox("Sorry, username or password not found", MsgBoxStyle.OkOnly, "Invalid Login")
Else
Form1.Show()
Me.Close()
myConnection.Close()
End If
Catch ex As Exception
MsgBox(ex.Message)
End Try
End If
End Sub
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
My.Settings.UserName = user_name.Text
My.Settings.Password1 = password.Text
My.Settings.Save()
provider = "Provider=Microsoft.ACE.OLEDB.12.0; Data Source="
dataFile = "D:\jyothi school\School Management\School Management\AddStudent.accdb"
connString = provider & dataFile
myConnection.ConnectionString = connString
myConnection.Open()
Dim cmd As OleDbCommand = New OleDbCommand("SELECT * FROM [Login] WHERE [user_name] = '" & My.Settings.UserName & "' AND [password] = '" & My.Settings.Password1 & "'", myConnection)
Dim dr As OleDbDataReader = cmd.ExecuteReader
If dr.HasRows Then
Form1.Show()
Me.Close()
Else
Me.Show()
'MsgBox("Sorry, username or password not found", MsgBoxStyle.OkOnly, "Invalid Login")
End If
myConnection.Close()
End Sub
Basically, i want the textboxes's values to be saved some where and then the application would use it to log in instead of making the user log in every time!
First , create 2 settings object named Username and Password.Now on form 1's login button click, add these codes :
my.settings.username=username.text
My.settings.password=password.text
My.Settings.Save
I suggest you to create a splash screen. Now add a background worker. Code for backgroundworker :
If My.Settings.Username = "" Then
LogIn.Show
Else
Try
Dim cmd as new oledbcommand("Select * rom [table] where [user_name]=#username and password=#password",connectionstring)
con.Open()
cmd.Parameters.Add("#username", OleDbType.VarChar).Value = my.settings.username
cmd.Parameters.Add("#password", OleDbType.VarChar).Value = my.settings.password
Dim adapter As New SqlDataAdapter(cmd)
Dim table As New DataTable
adapter.Fill(table)
if table.rows.count <=0 then
SHow warning message
Else
Form2.Show
con.close
Catch ex as exception
Msgbox(ex.message)
End try
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim con As New MySqlConnection("host=localhost; username=root; password=; database=wh_db")
Dim cmd As New MySqlCommand
Dim dr As MySqlDataReader
con.Open()
cmd.Connection = con
cmd.CommandText = " select pass from user where pass ='" & oldpass.Text & "'"
dr = cmd.ExecuteReader
If dr.HasRows Then
cmd.Connection = con
cmd.CommandText = " UPDATE user SET pass ='" & newpass.Text & "' where user = '" & user.Text & "'"
Else
MsgBox("Password is not correct")
End If
End Sub
I've not used MySQL for a while but have a look at this. It should give you some start into what you're after:
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim dr As MySqlDataReader
Using con As New MySqlConnection(yourConnectionString),
cmd As New MySQLCommand("SELECT pass FROM user WHERE pass = #pass", con)
cmd.Parameters.Add("#pass", MySqlDbType.VarChar).Value = oldpass.Text
con.open()
dr = cmd.ExecuteReader
End Using
If dr.HasRows Then
Using con As New MySqlConnection(yourConnectionString),
cmd As New MySQLCommand("UPDATE user SET pass = #pass WHERE user = #user", con)
cmd.Parameters.Add("#pass", MySqlDbType.VarChar).Value = newpass.Text
cmd.Parameters.Add("#user", MySqlDbType.VarChar).Value = user.Text
con.open()
cmd.ExecuteNonQuery()
End Using
Else
MsgBox("Password is not correct")
End If
End Sub
The reason you're not updating is because you haven't told the command to update. I've also implemented Using which I suggest you do and also look at parameters to stop SQL injection.
I've separated both statements into two Using statements as I feel this would be better rather than attempting to reuse the same object for both the SELECT and UPDATE command.
I'm sorry for disturbing you guys, but I had a question to ask. I'm currently doing a program where user which are in the access database can log in, the code is working but the problem is that when I debug I can only login using 1 user, when I try logging in using another user account it shows Login Invalid and I'm not sure why. I hope someone could pin point what am I doing wrong;
Here's my code;
Imports System.Data.OleDb 'provides classes to connect to the database
Imports System.Data
Imports System.IO
Public Class Login
Dim conn As New OleDbConnection
Dim cmd As New OleDbCommand
Function getcount() As Integer
Using conn As New OleDb.OleDbConnection _
("Provider=Microsoft.Jet.OLEDB.4.0;Data Source= " & Application.StartupPath & "\User.mdb")
'provider to be used when working with access database
conn.Open()
Dim cmd As New OleDb.OleDbCommand("Select COUNT(*) FROM UserProf_table", conn)
Return cmd.ExecuteScalar()
End Using
End Function
Private Sub Login_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
conn = New OleDbConnection
conn.ConnectionString = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source= " & Application.StartupPath & "\User.mdb"
conn.Open()
If getcount() = 1 Then
btnReg.Visible = False
Else
btnReg.Visible = True
End If
MsgBox(conn.State.ToString()) 'to check connection
End Sub
Private Sub btnSubmit_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnSubmit.Click
Dim idbx As String ' noted that ID is numbers
Dim pwd As String
idbx = idbox.Text
pwd = pwdbox.Text
With cmd
'Open Connection for executereader
If Not conn.State = ConnectionState.Open Then
conn.Open()
End If
'initialized database connection
.Connection = conn
.CommandText = "SELECT UserID, UserPwd FROM UserProf_table WHERE UserID = '" & idbox.Text & "' AND UserPwd = '" & pwdbox.Text & "'"
Dim dr As OleDbDataReader
dr = cmd.ExecuteReader
If dr.HasRows Then
dr.Read()
If idbx = dr.Item("UserID") And pwd = dr.Item("UserPwd") Then
idbx = SystemInformation.UserName
mainForm.Show()
Me.Hide()
Else
MsgBox("Password or username is incorrect")
idbox.Clear()
pwdbox.Clear()
End If
dr.Close()
End If
End With
'close connection
conn.Close()
End Sub
Private Sub btnReg_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnReg.Click
registerForm.Show() ' Register form
Me.Hide()
End Sub
End Class
Here's my database:
I login using the UserID and UserPwd. And is there a way for me to save the UserID do that I can use it in different form? Thank you in advance
You are always reading the whole username/password list!
You have forgotten a WHERE clause in :
SELECT UserID, UserPwd FROM UserProf_table
WHERE UserId = ???
You can login as the first user because it's the first row returned!
[Also: please don't store passwords as plain text]
You should change your sql command to retrieve only 1 record:
.CommandText = "SELECT UserID,UserPwd FROM UserProf_table WHERE UserId =" + idbx.trim()
Moreover, if you are using Visual Studio, you can use "Watch and QuickWatch Windows" in debug mode to show your variables and make sure they return expected values.
https://msdn.microsoft.com/en-us/library/0taedcee.aspx
This is my first question, by the way - and I'm not sure exactly how to ask, or say what's wrong. There's 3 things I can't sort so any help would be appreciated.
Module:
This and the first (login) form work as they are but I couldn't get either Form to reference con.connectionstring for them to use without having to re-use the string contained in "" (as they do below) - my attempts ended up with errors including saying that the state couldn't be changed as the connection was already open, but I'd like the same one string to be referenced from the Forms.
Module ConnectionModule
Public con As OleDb.OleDbConnection = New OleDb.OleDbConnection
Public da As OleDb.OleDbDataAdapter
Public ds As DataSet = New DataSet
Public Path As String = Application.StartupPath
Public Sub OpenDb()
con.ConnectionString = "Provider=Microsoft.ACE.OLEDB.12.0; Data Source=F:\Computing A2\CG4 Coursework\Greener Cleaning\dbCoursework.accdb"
con.Open()
If con.State = ConnectionState.Closed Then
MsgBox("Connection to db not made.")
End If
End Sub
Public CurrentUser As String = Nothing
End Module
The First Form:
Public Class LoginForm
Private Sub LoginForm_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
OpenDb()
con.Close()
End Sub
Private Sub btnLogin_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnLogin.Click
Dim ID As String = txtID.Text
Dim Pass As String = txtPassword.Text
If IsNumeric(ID) = False Or ID.Length > 4 Or Pass = Nothing Then
MsgBox("Staff ID is a 4-digit number and Password must not be blank.")
Else
Dim con As New System.Data.OleDb.OleDbConnection()
OpenDb()
con.ConnectionString = "Provider=Microsoft.ACE.OLEDB.12.0; Data Source=F:\Computing A2\CG4 Coursework\Greener Cleaning\dbCoursework.accdb"
Try
Dim sql As String = "SELECT * FROM tblStaff WHERE [StaffID]='" & ID & "' AND [Pword] = '" & Pass & "'"
Dim sqlCom As New System.Data.OleDb.OleDbCommand(sql)
'Open Database Connection
sqlCom.Connection = con
con.Open()
Dim sqlRead As System.Data.OleDb.OleDbDataReader = sqlCom.ExecuteReader()
If sqlRead.Read() Then 'Correct:
MenuForm.Show()
Me.Hide()
CurrentUser = ID
Else 'Incorrect:
MsgBox("Staff ID or Password incorrect.")
txtPassword.Text = ""
txtID.Text = ""
txtID.Focus()
End If
Catch ex As Exception
MsgBox("Database Connection Error.")
End Try
con.Close()
End If
End Sub
End Class
A form to change the password:
The problem here is that lblUser (A clarification for the user to tell them which password will be changed) only outputs the data already within the program as a variable: CurrentUser (as assigned upon successful login). No error is produced but the full name of the user isn't shown (or possibly read from the database).
I'm also unsure how the UPDATE SQL command should be contained within the second procedure, btnAccept_click, here. What the syntax is, basically. I haven't found a clear example to look at.
Imports System.Data.OleDb
Public Class PasswordForm
Private Sub PasswordForm_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
con = New System.Data.OleDb.OleDbConnection()
con.ConnectionString = "Provider=Microsoft.ACE.OLEDB.12.0; Data Source=F:\Computing A2\CG4 Coursework\Greener Cleaning\dbCoursework.accdb"
Dim Returned(2) As String
CurrentUser = CurrentUser
Dim cmd As OleDbCommand = New OleDbCommand("SELECT [Title], [Forename], [Surname] FROM tblStaff WHERE [StaffID]='" & CurrentUser & "'", con)
Try
con.Open()
Dim reader As OleDbDataReader = cmd.ExecuteReader()
If reader.HasRows Then
reader.Read()
'Makes db contents variables
Returned(0) = reader.Item("[Title]").ToString
Returned(1) = reader.Item("[Forename]").ToString
Returned(2) = reader.Item("[Surname]").ToString
End If
reader.Close()
Catch ex As Exception
Me.Hide()
MsgBox("Database Connection Error.")
Finally
con.Close()
End Try
lblUser.Text = "Current User: " & CurrentUser & Returned(0) & Returned(1) & Returned(2)
''Only outputs CurrentUser
End Sub
Private Sub btnAccept_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnAccept.Click
Dim Current As String = txtCurrent.text
Dim NewPass As String = txtNew.Text
'Verification
If txtNew.Text = txtConfirm.Text And NewPass.Length <= 20 Then
Dim cmd As OleDbCommand = New OleDbCommand("UPDATE tblStaff SET [Pword]='" & NewPass & "' WHERE [StaffID]='" & CurrentUser & "'", con)
End If
End Sub
End Class
Thank you, again, for anyone with ideas (especially exact code).
Oh and throughout what's here there are no errors thrown. Just missing content.
you are opening the connection in openDB() and you are trying to open it again in form1, this will throw the error you are getting. So comment all the con related lines in your form. Same comment for your passowrd form also.
'Dim con As New System.Data.OleDb.OleDbConnection()
OpenDb()
'con.ConnectionString = "Provider=Microsoft.ACE.OLEDB.12.0; Data Source=F:\Computing A2\CG4 Coursework\Greener Cleaning\dbCoursework.accdb"
Try
Dim sql As String = "SELECT * FROM tblStaff WHERE [StaffID]='" & ID & "' AND [Pword] = '" & Pass & "'"
Dim sqlCom As New System.Data.OleDb.OleDbCommand(sql)
'Open Database Connection
sqlCom.Connection = con
'con.Open()
...
end try
I have a Project in VB.NET as follows
Public Class MCARegis
Dim con As New OleDb.OleDbConnection()
Private Sub MCARegis_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
Dim da As OleDb.OleDbDataAdapter
Dim dbprovider As String = "Provider=Microsoft.ACE.OLEDB.12.0;Data Source=C:\Users\Taher\Documents\Visual Studio 2010\Projects\WindowsApplication1\WindowsApplication1\Database1.accdb;Persist Security Info=False;"
Me.con = New OleDb.OleDbConnection()
con.ConnectionString = dbprovider
con.Open()
MsgBox("opened")
End Sub
Private Sub btnadd_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnadd.Click
Try
Dim da As OleDb.OleDbDataAdapter
Dim dbprovider As String = "Provider=Microsoft.ACE.OLEDB.12.0;Data Source=C:\Users\Taher\Documents\Visual Studio 2010\Projects\WindowsApplication1\WindowsApplication1\Database1.accdb;Persist Security Info=False;"
Me.con = New OleDb.OleDbConnection()
con.ConnectionString = dbprovider
con.Open()
Dim sqlquery As String = "INSERT INTO MCA (URno,SName,Fname,CAddress,)" + "VALUES (" & CInt(txtUrn.Text) & ",'" & txtName.Text & "','" & txtFname.Text & "','" & txtCAdd.Text & "');"
Dim sqlcommand As New OleDb.OleDbCommand(sqlquery)
With sqlcommand
.CommandText = sqlquery
.Connection = con
.ExecuteNonQuery()
End With
MsgBox("Record Added")
Catch ex As Exception
MsgBox(ex.ToString)
End Try
End Sub
End Class
I am getting an error when i try to add values at the Insert into statement any suggestions on this?
system.data.oledb.oledbexception:Syntax error in INSERT INTO Statement at system.data.oledb.command.exceutecommandtexterrorhandling(oledbhresult hr)
at systems.data.oledb.oledbcommand.executecommandtext(object&executeresult)......
at system.data.oledb.oledbcomamand.executenonquery()
at line 29.
Thanks in Advance....
Replace "INSERT INTO MCA (URno,SName,Fname,CAddress,)" by "INSERT INTO MCA (URno,SName,Fname,CAddress)". You have specified a redundant comma