TableDefs.Refresh Method (DAO)
Updates the objects in the specified colletion to reflect the database's current schema.
To determine the position that the Microsoft Access database engine uses for Field objects in the Fields collection of a QueryDef, Recordset, or TableDef object, use the OrdinalPosition property of each Field object. Changing the OrdinalPosition property of a Field object may not change the order of the Field objects in the collection until you use the Refresh method
Use the Refresh method in multiuser environments in which other users may change the database. You may also need to use it on any collections that are indirectly affected by changes to the database. For example, if you change a Users collection, you may need to refresh a Groups collection before using the Groups collection.
A collection is filled with objects the first time it's referred to and won't automatically reflect subsequent changes other users make. If it's likely that another user has changed a collection, use the Refresh method on the collection immediately before carrying out any task in your application that assumes the presence or absence of a particular object in the collection. This will ensure that the collection is as up-to-date as possible. On the other hand, using Refresh can unnecessarily slow performance.