Provide code. Are you setting VBA string variables? Only variant type variable can hold Null. I don't allow empty strings in tables but if you want: Nz rst! FirstName, "". Add a comment. Active Oldest Votes. Value If the field that you are updating is numeric then you'll need to return a Zero value if null: Nz rst.
Improve this answer. So I guess the IsNull function isn't needed. Don't you mean the IsNull function is needed? IIf varFreight, 0, varFreight would return 0 if varFreight evaluated to True and would return varFreight if varFreight evaluated to False which it will do if it is Null. Argh - too early in the morning to be thinking of logical variables! You would use Null without the quotation marks e. Show 2 more comments.
You have it backwards if you really want to ensure the field is not Null or an empty string. Try this Last edited: Oct 28, EMP Registered User. Local time Today, Joined May 10, Messages EMP said:. RoyVidar Registered User. Local time Today, Joined Sep 25, Messages The question seems resolved, but I take the liberty of popping in and issue a little warning, and some suggestions.
Often I think "What If What if you at a later point of time decide to assign a string variable to a control? Strings cannot be Null, so if they are used, they "instantiate" as "", so when assigning "no string" to the control, it might become "", then what They will test both conditions. If I for some reason should need to perform differently if "" vs Null, then I'd use two tests. Text property of controls in for instance the on change event RoyVidar said:.
Local time Today, Joined Sep 11, Messages Im not nearly as experienced as anyone here but Ill tell you one thing I have learnt very quickly - never code as if you are trying to meet the needs of your most experienced user - but for your least experienced user. They are always going to do something you never could imagine could even be done causing you major problems in the process! For numeric fields, you could use a default value of 0, but that might cause trouble in the long run because functions handle Null and 0 differently see 7.
In addition, the Default property works only for new records. That means that you can't apply this solution to existing records. The truth is, it's usually easier to handle null values than it is to usurp them in this fashion. Don't try to find null values by equating them to anything else. The following expressions return an error, regardless of anything 's value:. As far as Access is concerned, Null doesn't equal anything.
This isn't always true outside Access. Once you decide that null values are acceptable, it's your job to accommodate them throughout the application. For instance, to find null values in a query, you'd enter Is Null in the appropriate field's Criteria cell. For instance, the use of IsNull in the following If statement handles a potential runtime error when null values exist:. Access won't always work with null values as you might expect. If you allow them, be prepared for surprises.
For instance, a simple expression such as. Instead of returning just the Subtotal, as you might expect, the expression returns Null. That's because any equation that encounters a null value will always return Null. Although it's a nuisance, it makes sense. You can't evaluate an unknown value. If your data contains null values, use the Nz function to protect your expressions from this error.
Specifically, Nz returns a value other than Null when it encounters Null as follows:. In this case, Nz returns 0 when Shipping equals Null. Use Nz in criteria and VBA expressions. Access projects don't support Nz. Any more feedback? The more you tell us the more we can help. Can you help us improve? Resolved my issue.
Clear instructions. Easy to follow. No jargon. Pictures helped. Didn't match my screen. Incorrect instructions. Too technical.
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