How to change this function to make it check if the database is already exist if not then create it?

Sub createDB(ByVal server As String, ByVal database As String, ByVal uid As String, ByVal pwd As String)
        Dim connectionString As String = "server=" + server + ";uid=" + uid + ";pwd=" + pwd
        Dim objConnection As New SqlConnection(connectionString)
        If objConnection.State = 0 Then _
            objConnection.Open()
        Dim ObjCommand = New SqlCommand("CREATE DATABASE " + database, objConnection)
        'ObjCommand.
        'ObjCommand.CommandText = sCmd
        ObjCommand.executenonquery()
        objConnection.Close()
    End Sub