[cifs-protocol] CAR: how are unique attributes determined?

[tridge at samba.org]

We would like to know how to work out which attributes in AD are
uniquely indexed.

We know that attributes like samAccountName, objectGUID and objectSID
are all unique. So if you try to create the following two records
using LDAP:

 dn: CN=test1,OU=User2,DC=vsofs8,DC=com
 sAMAccountName: test1
 objectClass: user

 dn: CN=test1,OU=User3,DC=vsofs8,DC=com
 sAMAccountName: test1
 objectClass: user

then windows AD implementation will return LDAP_ERR_ALREADY_EXISTS for
the second one, presumably because samAccountName is a unique
attribute. This makes sense, as you don't want two users with the same
account name.

What we can't work out is how to find the list of unique
attributes. We can't find anything in the schema that tells us an
attribute is unique. What part in the schema gives us that? Or is it
somewhere outside the schema?

Cheers, Tridge