ABCdatos

Necesito saber como introducir automáticamente un campo autonumérico que sea común a todas las tablas de una BD Acces, que a su vez se actualice cada vez que se abre el formulario de cada una de ellas y lo presente en este.

Define a new relationship between record sources in a data access page
If you add fields to the data access page and there isn't an existing relationship between the tables or queries they came from, Microsoft Access prompts you to define the relationship.

In the New Relationship dialog box, indicate which field you want to use to relate the record source you just tried adding to the data access page and the record source or sources that are currently part of the data access page's data definition. Also indicate the type of relationship between the two record sources.
Notes

Relationships you define in the New Relationship dialog box apply only to the current data access page. They are not added to the database; therefore, they won't appear in the Relationships window in a Microsoft Access database or the Database Diagram window in a Microsoft Access project.


In some cases, Access determines only one type of relationship is possible between the two record sources, so the other option will be disabled.