Rules for Creating Attribute Uniqueness

This section describes and gives examples of rules you follow when creating attribute uniqueness constraints. It contains these topics:

• Specifying Multiple Attribute Names in an Attribute Uniqueness Constraint

• Specifying Multiple Subtrees in an Attribute Uniqueness Constraint

• Specifying Multiple Scopes in an Attribute Uniqueness Constraint

• Specifying Multiple Object Classes in an Attribute Uniqueness Constraint

• Specifying Multiple Subtrees, Scopes, and Object Classes in an Attribute Uniqueness Constraint

To understand the examples in this section, refer to Figure 8-1.

Figure 8-1 Example of a Directory Information Tree

Text description of the illustration oidag079.gif

Specifying Multiple Attribute Names in an Attribute Uniqueness Constraint

When multiple attribute uniqueness constraints have different values in orcluniqueattrname, their effects are independent of each other.

For example, suppose that a user defines two attribute uniqueness constraints as follows:

Constraint1:

orcluniqueattrname: employee_id

Constraint2:

orcluniqueattrname: email_id

In this example, Constraint1 and Constraint2 enforce uniqueness on the specified attribute within their own attribute uniqueness scopes. Constraint1 and Constraint2 are independent of each other.

Specifying Multiple Subtrees in an Attribute Uniqueness Constraint

When multiple attribute uniqueness constraints have the same values in orcluniqueattrname, orcluniquescope and orcluniqueobjectclass, but different values in orcluniquesubtree, the union of subtree scopes specified by those attribute uniqueness constraints is checked.

For example, refer to Figure 8-1. Suppose that a user defines two attribute uniqueness constraints as follows:

Constraint1:

orcluniqueattrname: employee_id
orcluniquesubtree: o=sales, c=us, cn=root
orcluniquescope: onelevel

Constraint2:

orcluniqueattrname: employee_id
orcluniquesubtree: o=hr, c=euro, cn=root
orcluniquescope: onelevel

In this example, the attribute uniqueness on employee_id is enforced against all entries under subtree o=sales,c=us,cn=root and o=hr,c=euro,cn=root--that is, the directory server enforces the unique value of the employee_id attribute for employee1, employee2, employee5 and employee6.

Specifying Multiple Scopes in an Attribute Uniqueness Constraint

When multiple attribute uniqueness constraints have the same values in orcluniqueattrname, orcluniquesubtree and orcluniqueobjectclass, but different values in orcluniquescope, the attribute uniqueness constraint with the largest search scope takes effect.

For example, referring to Figure 8-1, suppose that a user defines two attribute uniqueness constraints as follows:

Constraint1:

orcluniqueattrname: employee_id
orcluniquesubtree: c=us, cn=root
orcluniquescope: onelevel

Constraint2:

orcluniqueattrname: employee_id
orcluniquesubtree: c=us, cn=root
orcluniquescope: sub

In this example, the attribute uniqueness on employee_id is enforced against all entries under the subtree c=us,cn=root and the entry c=us,cn=root itself. Note that this is the same as if the user had defined only Constraint2.

Specifying Multiple Object Classes in an Attribute Uniqueness Constraint

When multiple attribute uniqueness constraints have the same values in orcluniqueattrname, orcluniquesubtree, and orcluniquescope, but different values in orcluniqueobjectclass, then the union of attributes belonging to those object classes is checked.

For example, referring to Figure 8-1, suppose that a user defines two attribute uniqueness constraints as follows:

Constraint1:

orcluniqueattrname: employee_id
orcluniquesubtree: c=us, cn=root
orcluniqueobjectclass: person

Constraint2:

orcluniqueattrname: employee_id
orcluniquesubtree: c=us, cn=root

In this example, the attribute uniqueness on employee_id is enforced against all entries under the subtree c=us,cn=root and the entry c=us,cn=root itself, no matter what object class those entries belong to. Note that Constraint2 specifies no orcluniqueobjectclass attribute, which is the same as specifying all object classes.

Specifying Multiple Subtrees, Scopes, and Object Classes in an Attribute Uniqueness Constraint

When multiple attribute uniqueness constraints have the same values in orcluniqueattrname, but different values in orcluniquesubtree, orcluniquescope, and orcluniqueobjectclass, the union of entries that belong to the attribute uniqueness scopes of different constraints are checked.

For example, referring to Figure 8-1, suppose that a user defines two attribute uniqueness constraints as follows:

Constraint1:

orcluniqueattrname: employee_id
orcluniquesubtree: o=sales, c=us, cn=root
orcluniquescope: onelevel
orcluniqueobjectclass: person
 

Constraint2:

orcluniqueattrname: employee_id
orcluniquesubtree: c=euro, cn=root
orcluniquescope: sub
orcluniqueobjectclass: organization

In this example, the attribute uniqueness on employee_id is enforced against the following:

• All entries under the subtree o=sales,c=us,cn=root where their object class belongs to person

• All entries under subtree c=euro,cn=root and the entry c=euro,cn=root itself where their object class belongs to organization