http://blogs.msdn.com/b/dynamicsaxscm/archive/2012/09/11/avoid-index-length-issues-with-inventdim.aspxIn Microsoft Dynamics AX we use indexes to ensure uniqueness. An example of this is the DimIdx index in InventDim , where all dimension fields are included to ensure that only a single record exists for a given set of dimensions. However, the SQL Serveren-USTelligent Evolution Platform Developer Build (Build: 5.6.50428.7875)