ACC: Null Value Does Not Pass Validation Rule (117542)

CAUSE

This behavior only occurs when adding a new record with two fields, one of which has a data type of AutoNumber (or Counter in version 2.0).

This behavior differs from that of Microsoft Access version 1.x. In Microsoft Access 1.x, a Null value is accepted for a field, even if "Or Is Null" is not part of the validation rule.

RESOLUTION

Include "Or Is Null" as part of the validation rule for the field. For example, a validation rule for a text field could be:

   "A" Or "B" Or Is Null

MORE INFORMATION

Steps to Reproduce Behavior

Create the following new table and save it as Table1:

      Table: Table1
      ---------------------------------------------------
      Field Name: ID
         Data Type: AutoNumber (or Counter in version 2.0)
      Field Name: Code
         Data Type: Text
         Validation Rule: "A" Or "B" Or Is Null

View the table in Datasheet view.
Select the Code field. Type A and press ENTER. Note that you can move to the next record.
In the next record, press TAB to move to the third record. Note that you cannot move to the next record because the Code field cannot initially be Null. This is because there is only one user input field defined in this table, and the record cannot be saved until it has received some input.
Select the Code field in the second record. Type A and press ENTER. Delete the A from the field, and press TAB. Note that you can move to the next record now because the record was initially saved with data.

REFERENCES

For more information about the ValidationRule property, search for "ValidationRule property," and then "Create a validation rule for a control" using the Microsoft Access 97 Help Index.

For more information about using Null values in a validation rule, search for "ValidationRule property," and then "ValidationRule, ValidationText Properties" using the Microsoft Access 97 Help Index.