How to check if the records are exist in table and store it on another table?

I have already a form in VB.net with textbox1.text and buttons from 0 to 9 (as calculator). I would like to have my textbox1.text asking a question three times inside the text itself Enter STD ID , Enter SS ID Enter car #  and check the entering in the database if it is exits or not !
1- If it is exist;
Save him in the table called sign and give him a seat from (1 to 5) if the seat is available and if not let him wait?
con.Open()
 
        MsgBox("A Connection to the Database is now open")
 
        Dim ds As New DataSet
        Dim da As OleDb.OleDbDataAdapter
        Dim sql As String
 
        sql = "SELECT * FROM table"
        da = New OleDb.OleDbDataAdapter(sql, con)
        da.Fill(ds, "northwind")
 
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con.Close()

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calc.jpg
aiman_alnasirAsked:
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CodeCruiserCommented:
I dont understand your question fully but here is an example of how to check if a record already exists in database.


Dim dbcon as new OleDBConnection(connectionstring)
dbcon.open
Dim dbcmd as new OleDBCommand
dbcmd.connection = dbcon
dbcmd.commandtext = "Select Count([Name]) From [Employee] Where [Name]='" & txtName.Text & "'"
Dim Count as Integer = dbcmd.ExecuteScaler()
If Count > 0 Then
   Messagebox.show("This Employee already exists")
End If
dbcmd.dispose
dbcon.dispose

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aiman_alnasirAuthor Commented:
This is a good step to start;
Could you please see my code below and fix any errors;
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Dim Show1, Show2, Show3 As String
        Show1 = InputBox("Enter STD ID Number: ")
        a = Show1
        Show2 = InputBox("Enter SS ID Number: ")
        b = Show2
        Show3 = InputBox("Enter car Number: ")
        c = Show3

        dbcmd.Connection = con
        dbcmd.CommandText = "Select Count(*) From table Where STD ='" & a & "' and SS = '" & b & "' and car = '" & c & "'"
        ' please note the error message (ExecuteScaler is not a member of System.Data.OleDb.OleDbCommand)    
        Dim Count As Integer = dbcmd.ExecuteScaler()
        If Count > 0 Then
            MessageBox.Show("This Employee already exists")
        End If
        dbcmd.Dispose()
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CodeCruiserCommented:
My typo
Its
dbcmd.ExecuteScalar()
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aiman_alnasirAuthor Commented:
Thanks dude,
Now, do you know some code to reserve a space or a seat or a time per day on VB.net? So, whenever the students are available on the database it will allow him to reserve a specific time or seat. For example, if we have 5 seats, 5 students are allow to pick one seat for each and any other students who came after will keep him in the waiting list.
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CodeCruiserCommented:
There is no quick code for that functionality. This is what your application will be doing and you need to implement it based on the requirements.
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