I have the code below which does work, but I need to add further functionality to it. The functionality I want to add to it is the text I have commented in the code below.
Dim objSQLConnection As SqlConnection
Dim objSQLCommand As SqlCommand
Private Sub Page_Load(ByVal sender As System.Object, ByVal e As System.EventArgs)
Dim intID As Integer = CType(Request.Form("ID"), Integer)
Dim strHeading As String = CType(Request.Form("Heading"), String)
Dim intState As Integer = CType(Request.Form("State"), Integer)
Dim strUser As String = CType(Request.Form("User"), String)
objSQLConnection = New 开发者_StackOverflow中文版SqlConnection(System.Configuration.ConfigurationManager.AppSettings("connString"))
''#count if records with this user already exist in the database below
If intState = 1 Then
objSQLCommand = New SqlCommand("insert into table1 (id, heading, user) values (@intID, @strHeading, @strUser)", objSQLConnection)
objSQLCommand.Parameters.Add("@intID", SqlDbType.Int, 4).Value = intID
objSQLCommand.Parameters.Add("@strHeading", SqlDbType.VarChar, 255).Value = strHeading
objSQLCommand.Parameters.Add("@strUser", SqlDbType.VarChar, 3).Value = strUser
ElseIf intState = 0 Then
objSQLCommand = New SqlCommand("delete from table1 where id = @intID and user = @strUser", objSQLConnection)
objSQLCommand.Parameters.Add("@intID", SqlDbType.Int, 4).Value = intID
objSQLCommand.Parameters.Add("@strUser", SqlDbType.VarChar, 3).Value = strUser
End If
objSQLCommand.Connection.Open()
objSQLCommand.ExecuteNonQuery()
objSQLCommand.Connection.Close()
End
Before the if statement, I want to find out if the database already has records with the username in the strUser variable. What is the best way to go about doing this?
I'm not going to do all of this for you but a simple way to check the count is store the result of a stored procedure (SQL Server) into a SqlDataReader and check if the count > 0 or if HasRows = True.
With (myObjectCommand)
.Parameters.Add("@strUser", SqlDbType.Varchar, 3).Value = myUser
myReader = .ExecuteReader
End With
if myReader.HasRows
return true ?
end if
Simple enough. Just do ExecuteScalar on the database with a query like "Select field1 from table where username = @username" and pass the strUser into the query object. Then save the scalar result into a variable (result). Then you can do if result is <> "", do such and such.
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