A fiels with "unique" in the field definition can contain doubles:

1) when duplicating a record

2) when autonumbering is used, and the value to be filled in is altered in field definition.

In both cases no warning is issued to inform you about a double in a unique field.

I this a bug, or should i protect my "unique" field in a other way??

Thanks for all advice

Personally I NEVER rely on someone or something else to check my unique values. I will always run the data through a validation script to insure that it passes. This also allows you to lead the user through the steps necessary to correct the problem.

When talking about Filemaker, the term "Bug" can be somewhat subjective. As it turns out, field validation is only done when a user manually entering data into or editing the field. So validation won't be done when a record is duplicated, or when the field is changed in a script etc.

If you need to ensure uniqueness, don't allow the user to duplicate records, and don't rely on field validatation. Script everything. And look at Captkurt's article on unique ID's in the articles forum.

When duplicating a record, an auto enter value as a serial number is updated/changed, but an auto enter by calculation is not: that value is simply duplicated with the record. I wonder why this difference is, does not seem logic to me, but it's a fact.

When you duplicate a record, script this always, and attach to a button, and urge your users never to use the FM-menu Duplicate Record script step. And in that 'duplicate record' script, the set field for your unique ID-field (some calculation) must be incorporated.

Harryk