In FMP 7/8, pertaining to an auto-enter value in a field, what is the difference between selecting a calculated result and a looked up value? Don't they both result in a field entry that is changeable? Of course, I know that a field with a looked-up value is subject to relookup. But at the beginning, when a record is created, is there a difference in the value or the field?

At the onset, no differnce, but if you want to maintain the original value, you can use auto-enter calc set as "Do Not Replace Field Contents", that way whenever there's an update, the original value remains unchanged. This is a very good feature if you'd like to STORE the value of a field from a related table or file. The reason why you may want to store this value is because filemaker calculation cannot be set store a value from another table but this will enable you to do that. Very good for maintaining history.

Ok, slow down here.

The checkbox "Do not replace existing value for field (if any)" should mean, Don't allow this auto-entered value to replace a previously-entered value, right?

Of course, this seems silly to me if this is activated by the creation of a new record, what previously-entered value could be in a non-calculating field anyway?

Please note that I mentioned UPDATE as compared to NEW. I just wanted to alert you that there's cases where it comes in handy. Stored calcs export much faster than unstored and in most cases if you want to force a stored calculation based on a related field is to use this feature.

Ok, slow down here.

The checkbox "Do not replace existing value for field (if any)" should mean, Don't allow this auto-entered value to replace a previously-entered value, right?

Of course, this seems silly to me if this is activated by the creation of a new record, what previously-entered value could be in a non-calculating field anyway?

With the box checked, auto-entry will only take place when the field to be auto-entered has no value. This would be the case in a new record and would also be the case in an existing record whose field has no value.

The advantage of the lookup is for a line item table you can and most likely will have price changes. You will always want the price to stay the same for a specific line item per date. A calculated value can change. A lookup would not change unless you do a relookup.

John

The advantage of the lookup is for a line item table you can and most likely will have price changes. You will always want the price to stay the same for a specific line item per date. A calculated value can change. A lookup would not change unless you do a relookup.

John

It looks to me like you are confusing auto-enter calc and "regular" calculation field. An auto-enter calc is basically the same as a lookup. That is, it does not change by itself even if the unit price changes in the product table. An auto-enter calc still has to be triggered, almost exactly like a lookup has to be triggered.

However, I still insist that auto-enter calc gives you more control than a lookup. When you triger a lookup, all the fields set to lookup based on that relationship are updated whereas, for an auto-enter calc, if it is set not to replace, it will only update those fields that are empty and leave the rest unchanged. I believe that gives you a better control and if you want it to behave like a lookup, just leave the box checked (by default).

Edited January 15, 200620 yr by Guest

Here's an old thread about this subject, particularly how Lookups and Auto-Enter Calcs seem to perform differently:

http://fmforums.com/forum/showtopic.php?tid/144651

And another about the use of the new Lookup() function:

http://fmforums.com/forum/showtopic.php?tid/153970