2.6 Attributes

Attributes are the properties that describe objects in Documentum. For example, for a news article, the name of its author and its creation date can be considered its attributes.

It should be noted that all persistent objects stored in the Docbase are eventually subtypes of the internal persistent object type.

The persistent object type has three attributes that all subtypes inherit. r_object_id is specifically what everyone working with Documentum should understand:

  • r_object_id is a unique identifier generated by the Content Server and assigned to all objects at the time of their creation. It should be noted that within the Docbase, no two objects can share the same r_object_id.
  • i_is_replica and i_vstamp are internal server-generated attributes normally not required in typical applications.

2.6.1 Object ID (Object Identifier: r_object_id Attribute)

Object IDs are generated by the Content Server whenever a new object is created in a Docbase. These are represented as 16-character strings, used to uniquely identify objects within a Docbase. The first two characters in the object ID of an object are called type identifiers and represent the object type of the object in question.

For example, consider a dm_document object having the r_object_id 090015558000c629. The first two characters (09) in this object ID represent the type of the object: dm_document in this example. The table shown in figure 2.6 shows some common Documentum object types and their type identifiers.

Object type

Type identifier

ACL (dm_acl)

45

Alias Set (dm_alias_set)

66

Cabinet (dm_cabinet)

0c

Content (dmr_content)

06

Document (dm_document)

09

Folder (dm_folder)

0b

Group (dm_group)

12

Job (dm_job)

08

Lifecycle policy (dm_policy)

46

Method (dm_method)

10

User (dm_user)

11

Workflow process (dm_process)

4b

SysObject (dm_sysobject)

08

2.6.2 Attribute Types

Attributes can be divided into various categories.

  • Single valued and Repeating attributes: Single valued attributes, as the name suggests, can have just one value. An example of this would be the title or the subject of a document. Repeating attributes can hold multiple values. An example of this would be the keywords for a document. A document for example can have many keywords to describe it, unlike its title which can be just one.
  • Read-write and Read-only attributes: Read-write attributes can be modified by applications as well as users. Examples: title, object_name, a_content_type, etc.

Note

It should be noted that attributes starting with a_ would typically be used by application developers and not by users.

Read-only attributes are managed by the server and it is advisable not to tamper with these. These can, however, be read by applications.Examples: r_object_id, r_creation_date, i_contents_id, etc.

  • Computed attributes: Apart from the attributes of persistent objects, which are stored in the Docbase, Content Server computes certain attributes for the objects. These attributes are called computed attributes and are not persistently stored in the Docbase but generated by the server at run time. Examples: _alias_set, _policy_name, etc.

Object Type

Attribute names

Persistent Object

r_object_id

i_is_replica

i_vstamp

SysObject (dm_sysobject)

r_object_type

r_modify_date

r_creation_date

r_version_label

i_chronicle_id

object_name

a_effective_date

a_expiration_date

title

subject

authors

keywords

Folder (dm_folder)

r_folder_path

Cabinet (dm_cabinet)

is_private

User (dm_user)

user_name

user_os_name

user_group_name

Group (dm_group)

group_name

users_names

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