Function to check if Input is in column in SQL Server database - sql

Question

Okay, I'm creating an application which requires the user to input there Gamer-Tag during the registration process. Only 'Members' of a group may have access to the program and so I need the application to refuse anyone who's Gamer-Tag is not in the SQL Server database.
I adapted a function I created to log-in with your details and changed it to check if the Gamer-Tag is on the database, but I'm receiving a strange error:
The column 'Gamer_Tag' is not a Member of 'Members_Details' Table.
Please note, that's an error and not what I am wanting it to do. It's saying the column 'Gamer_Tag' isn't in the table, but I know it is! I've checked spelling and spacing and everything's as it should be, so I'm assuming it's something wrong with the code.
The (relevant) register button code:
(Note, RegUserName.Text is the textbox that contains the users Gamer-Tag.
Dim dbManager As New DatabaseManager()
If dbManager.CheckGamerTagisMember(RegUserName.Text) Then
MsgBox("Gamer-Tag Not A Member.")
My.Settings.RegisterCount = 1
My.Settings.Save()
RegisterBTN.Enabled = True
MsgBox("Registration Failed.")
GoTo Ender
Else
MsgBox("Gamer-Tag is A Member.")
GoTo Ender
End If
And the function this is calling:
Public Function CheckGamerTagisMember(ByVal gamertag As String) As Boolean
Connection = New SqlConnection("Data Source =" & My.Settings.ServerIP & ";Initial Catalog=Members_Details;Integrated Security=False;User=" & My.Settings.UserName & ";Password=********;")
Connection.Open()
Dim gamertagDatSet As New DataSet()
usersDataAdapter.FillSchema(gamertagDatSet, SchemaType.Source, "Members_Details")
usersDataAdapter.Fill(gamertagDatSet, "Members_Details")
Dim table As DataTable = gamertagDatSet.Tables("Members_Details")
For i As Integer = 0 To table.Rows.Count - 1
Dim currentUsergt As String = table.Rows(i)("Gamer_Tag").ToString.Trim()
If (currentUsergt = gamertag) Then
gamertagDatSet.Dispose()
Connection.Close()
Return True
End If
Next
gamertagDatSet.Dispose()
Connection.Close()
Return False
End Function
And to prove the column is in the table, here's the table's columns;
I'm new to structuring my code into classes, so I could be 'passing' things around wrongly.
Any help would be much appreciated!

Answer 1

I haven't a clue what the issue is with your code (there's probably something else going on which is not evident in your question).
But I will say that the approach you are taking will not scale well. With each registration, you are downloading the entire table to the program and then scanning through the rows, one by one, looking for an ID.
It would be much easier to write a simple stored procedure to do this for you. You would also get the advantage of using indexes. For example:
CREATE PROCEDURE spGetMembers_ID
#Gamer_Tag varchar(255)
AS
SET NOCOUNT ON;
SELECT Members_ID
FROM Members_Details
WHERE Gamer_Tag = #Gamer_Tag
GO
You can call this stored proc this way:
Dim getMembers_IDCommand As New SqlCommand("TestProcedure", Connection)
getMembers_IDCommand.CommandType = CommandType.StoredProcedure
Dim gamerTagParam As SqlParameter = getMembers_IDCommand.Parameters.Add("#Gamer_Tag", SqlDbType.VarChar, 255)
gamerTagParam.Value = gamertag
SqlDataReader result = getMembers_IDCommand.ExecuteReader();
Dim exists As Boolean = myReader.Read()
result.Close()
Return exists
There, of course, many ways to execute a stored procedure and get the results. Several are documented here. But the point is that a stored procedure is faster, more scalable and generally faster.