Microsoft KB Archive/117542

= ACC: Null Value Does Not Pass Validation Rule =

Article ID: 117542

Article Last Modified on 1/19/2007

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APPLIES TO


 * Microsoft Access 2.0 Standard Edition
 * Microsoft Access 95 Standard Edition
 * Microsoft Access 97 Standard Edition

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This article was previously published under Q117542



Novice: Requires knowledge of the user interface on single-user computers.



SYMPTOMS
You cannot leave a field blank, or Null, in a table's Datasheet view if the field has a validation rule.



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



STATUS
This behavior is by design.



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.</li> 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.</li></ol>

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