To keep a record unique with respect to three fields, we setup:

• hidden formula field to capture the three part unique key
• visible text field with unique specified to hold the key
• field update to move the formula field to the unique field
• workflow rule to fire the field update on insert or whenever any of the three parts change.

This scheme works fine, however when running a test method with a bulk insert, the bulk insert fails.

The interesting thing is the insert call does not fail if records are inserted one at a time in a for loop.

The insert call does fail when the records are collected in a List in the for loop and inserted all at once.

I speculate that somehow the uniqueness key is cached and verified as unique more than once.

Perhaps the second time it gets verified agianst its cached-recently-verified value, as the error message indicates that the unique record id associated with the uniqueness violation is non other than the just inserted record. A typical error message looks like:

DUPLICATE_VALUE, duplicate value found: Unique_Commodity_LDC_LDC_Account__c duplicates value on record with id: a06Q00000009W5g 

The record id a06Q00000009W5g was generated as a result of the insert.

Any ideas on what might be causing the uniqueness-violation-on-bulk-insert behaviour?

Thanks