VB.net and Mysql Login Problem Using Two Tables - mysql

Question

How can i login using doctor level in his table.Because everytime i log the receptionist form is always popping even when i log using the user and pass of the doctor maybe my syntax is wrong please help me
PS: Doctors Forms and Receptionists Forms are different.
This is my code:
Try
mycon.Open()
Dim query1 As String
Dim query2 As String
Dim name As String
query1 = "SELECT * FROM receptionisttbl"
command = New MySqlCommand(query1, mycon)
reader = command.ExecuteReader
With reader
.Read()
If .Item("level") = "1" Then
With reader
.Read()
name = .Item("name")
End With
MsgBox("Welcome " + name)
Form1.Show()
command.Dispose()
reader.Close()
mycon.Close()
Else
mycon.Open()
query2 = "SELECT * FROM doctortbl"
command = New MySqlCommand(query2, mycon)
reader = command.ExecuteReader
With reader
.Read()
If .Item("level") = "2" Then
With reader
.Read()
name = .Item("name")
End With
MsgBox("Welcome " + name)
Form2.Show()
command.Dispose()
reader.Close()
mycon.Close()
End If
End With
End If
End With
Catch ex As Exception
MsgBox(ex.ToString)
Finally
mycon.Dispose()
End Try

Answer 1

First, let's consider your requirements.
Provide a login form to validate users.
If the user is valid (userName and matching password are found in the database) then display a Form based on the level of the user.
Considering the requirements look at the design of the table in the database. Let's call it MDUsers.
Now to the columns.
UserName as an VarChar size 100 and Primary key of the table
UserPassword as VarChar size 100
Level an Integer
Now you have fields for all the data you need for your requirements.
Add some sample data to your table.
Next think about what you need from the user to accomplish your requirements. Design your user interface accordingly.
Your login form will have 2 text boxes (userName and password) and a button (Login).
Then you need to think about the code for the Login button.
You need to connect to your database and check if there is a match to userName and password. Once you find a match you only need to retrieve a single piece of data to complete your requirements, the level.
Now how can we ask the database to do all that?
Select level From MDUsers Where userName = #userName And UserPassword = #pword;
Since userName is the Primary Key of the table we know we will find no more than one record with that userName. If the password matches too then we have a valid user and we will return the single piece of data, level for that record.
Using...End Using blocks ensure that your database objects are closed and disposed even if there is an error. You can pass your connection string directly to the constructor of the connection and pass the query string and connection to the constructor of the command.
Always use parameters.
Since we only need a single piece of data we can use .ExecuteScalar
Private Sub OpCode()
Dim retVal As Object
Using cn As New MySqlConnection("Your connection string"),
cmd As New MySqlCommand("Select level From MDUsers Where userName = #userName And UserPassword = #pword;", cn)
cmd.Parameters.Add("#userName", MySqlDbType.VarChar, 100).Value = txtName.Text
cmd.Parameters.Add("#pword", MySqlDbType.VarChar, 100).Value = txtPassword.Text
cn.Open()
retVal = cmd.ExecuteScalar
End Using
If retVal Is Nothing Then
MessageBox.Show("Login failed")
Return
End If
If CInt(retVal) = 1 Then
Form1.Show()
ElseIf CInt(retVal) = 2 Then
Form2.Show()
Else
MessageBox.Show("Level not recognized")
End If
End Sub
You will have to check MySql rules for column names and table names being aware of reserved words.