<p> CSC400</p><p>Chapter 5 - Key Terms</p><p> Abstract class: a class that cannot be instantiated (no objects can be created), existing only to allow subclasses to inherit its attributes, methods, and associations.  Aggregation: whole-part relationship between an object and its parts in which the parts can exist separately.  Association class: a class that represents a many-to-many relationship between two other classes.  Binary association: a relationship between two different types of things, such as a customer and an order.  Composition: whole-part relationship in which the parts cannot be dissociated from the object.  Compound attribute: an attribute that contains a collection of related attributes.  Concrete class: a class that can be instantiated (objects can be created).  CRUD: acronym of create, read, update, and delete.  Destination: an external agent that receives data from the system.  Domain model class diagram: a UML class diagram that shows the things that are important in the users’ work: problem domain classes, their associations, and their attributes.  Elementary business processes (EBPs): tasks that are performed by one person in one place, in response to a business event, that add measurable business value and leave the system and its data in a consistent state.  Event: an occurrence at a specific time and place that can be described and is worth remembering.  Event decomposition: a technique analysts use to identify use cases by first focusing on the events a system must respond to and then looking at how a system responds.  Event table: a catalog of use cases that lists events in rows and key pieces of information about each event in columns.  External event: an event that occurs outside the system, usually initiated by an external agent or actor.  Identifier (key): an attribute that uniquely identifies a thing compound attribute an attribute that contains a collection of related attributes.  Location diagram: a diagram or map that identifies all of the processing locations of a system.  N-ary association: a relationship among n (any number of) different types of things.  Perfect technology assumption: the assumption that events should be included during early iterations only if the system would be required to respond under perfect conditions.  Response: an output, produced by the system, which goes to a destination.  Source: an external agent that supplies data to the system  State event: an event that occurs when something happens inside the system that triggers the need for processing.  System controls: checks or safety procedures put in place to protect the integrity of the system  Temporal event: an event that occurs as a result of reaching a point in time.  Ternary association: a relationship among three different types of things.  Trigger: a signal that tells the system that an event has occurred, either the arrival of data needing processing or a point in time.  Unary (recursive) association: a relationship between two things of the same type, such as one person being married to another person.  Use case–domain class matrix: a table that shows which use case requires access to each domain class.  Use case–location matrix: a table that describes the relationship among use cases and the locations in which they are performed.  Whole-part hierarchies: hierarchies that structure classes according to their associated components.</p>