Understand Class Library Concepts

Understanding the Class Library concepts enables you to manage the database, using the Admin Tool.

Associative Object

For an Object to exist in the AIM database, it must have:

• A Class ID.

• At least one unique identifier.

  • A long descriptive name.

  • A Context or namespace for the ID.

  • A Revision name or number.

    Object Identifier and Context

An Object Identifier is a unique ID for an Object in the database. By default, the objects assume IDs in the global or null Context. Typically, a Root Object's ID defines a context, while importing packages into the database.

The following figure depicts an Objects ID, with reference to a Context:

If one database contains multiple plants or projects' data, defining object identifier and its context avoids a data clash.

Note: The convention for defining an Object Identifier, with reference to a context, is to use a | (vertical bar) between the context and the object identifier.

For example, WCP|P-101 (Indicates the ID of the Object FUEL PUMP of a class of PUMP, in the context of a West Cambridge Plant of a class of PLANT).

Classes

A class defines the category or type of object in the class library or the Reference Data Library (RDL). The following are the characteristic features of the classes:

• Classes are pre-defined in the Class Library.

• Objects can belong to multiple classes. For example, an object can be a part of a class, ROTARY PUMP as well PRIMARY FEED PUMP.

• Objects can be categorized to classes, based on their associations.

• Associations between the objects and classes can be bi-directional, but they are always defined with the object as the source.

  

The following figure shows the two types of associations, based on which the objects are classified:

Unclassified Objects and UNKNOWN Class

An Object in the AIM database must have at least one Identifier and one Class. If an Object exists without a Class in the database after a complete data import, then it indicates an error in the data import. The Objects without a Class will be shown as UNKNOWN.

Alias Identifiers

If an Object has more than one Identifier, it represents an Alias Identifier. An Object must have at least one Identifier. More than one Identifier can be assigned to an Object, or any of its Identifier can be deleted. However, the last remaining identifier cannot be deleted, without deleting the Object itself.

If an Object has multiple Identifiers, AIM displays the Identifier that you have chosen as the Preferred Identifier in the Admin Tool. You can choose to display another Identifier, by changing the settings in the Admin Tool.

Objects Common to Multiple Projects

An Object that is common to two separate plants should be given two identifiers, each with the context of the respective plant. The ID can be same or different in each context. However, the identifier combination (Context+ID) must be unique within the AIM Workhub database.