Appendix A: The Rules

© 2007 The Smart Method Ltd

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3: Field properties

3-1

Primary keys are always meaningless and have the data type: AutoNumber.

3-2

The default value of non-required foreign keys should be Null and not 0 (the Access default).

Since the data type of primary keys must always be AutoNumber it follows that the data type of

foreign keys are always numeric. It will not be possible to add records to a child table if it has a

foreign key (that forms part of a constrained relationship) with a value of 0.

3-3

At least one (non primary key) field must always be required.

This rule will prevent users from accidentally creating entirely blank records. While observing this

rule avoid non-essential required fields, only making them so when business rules demand it.