CIOM-2010

CIOM-2010 - CSCI585 Classified Interrelated Object Model...

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CSCI585 Classified Interrelated Object Model Dennis McLeod and Shan Gao University of Southern California 1. Introduction CIOM is a simple object model, containing the major components of semantic and object-based database models; it is essentially a modified subset of SDM [1]. With the basic structures, semantic integrity constraints, and operations of SDM, CIOM intends to model the real world and capture the semantics of an application environment. 2. Classes A class is defined as a collection of objects (information units). This collection is a logically homogeneous set of one type of objects. The objects of a class are said to be the members of the class. 2.1 Class Name The name of a class is used to identify the class from others. A class name can be any string of symbols that uniquely represents the nature of this class. In CIOM, the class name is written inside of an oval to represent the class. 2.2 Built-in Classes There are several built-in classes predefined in CIOM. They are often used as the value classes for basic attributes. For example, STRINGS is the class of all strings over the set of alphanumeric characters. NUMBERS is the class of all numeric values of integers, real or complex numbers. BOOLEANS is the class of two values “True” and “False”. Other classes such as INTEGERS, DATES, IMAGES, AUDIOS, VIDEOS are defined as well. Their meanings are self-explanatory. 2.3 Member Attributes Member attributes are the common aspects of members of a class. A member attribute describes each and every member of the class. For example, every person has an age, so “Age” is one common attribute of the class “People”. The Dot Notation is used to denote attributes. The above attribute can be written as People . Age. In CIOM, an attribute is drawn as an arrow pointing from one class to another as shown in Figure 1. This is understood as: Class C1 has an attribute A whose value class (set of possible values) is C2. Figure 1. A member attribute C1 C2 A
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2.3.1 Attribute Names Each attribute has a name that uniquely identifies that attribute from other attributes of the same class. Similar to a class name, an attribute name can be any string of symbols. 2.3.2 Attribute Value Classes The value class of an attribute is the set of all possible values that applies to the attribute. This set can be any built-in classes or any user-defined classes as well. For example, the value class of People . Age is INTEGERS, while the value class of People . Parents is the class People itself. 2.3.3 Inverse Attributes In a CIOM schema, attributes always have inverses, and are usually shown in pairs. In each pair, each attribute is said to be the inverse of the other. This relation is specified symmetrically. The inverse attribute of attribute A is denoted as A -1 . In figure 2, attribute A and A -1 are drawn as a pair of inter-linked arrows. C1 is the value class of attribute A -1 . Figure 2. Inverse attributes
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CIOM-2010 - CSCI585 Classified Interrelated Object Model...

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