CIS 520

Semantic Objects

Class #4

A Semantic Object is a collection of attributes that sufficiently describe a distinct identity. The collection and sufficient are defined by the user.

Semantic Objects are independent and separate entities for which users wish to collect and maintain data.

An attribute is a data item. For example: name, address, phone, age, position, and such.

Simple Attributes have a single value.

Composite Attributes have multi-values.

Group attributes are composites of other attributes

Semantic Object attributes establish links to other objects. Always in pairs.

An instance is an actual occurrence of the object.

Attributes have cardinality.

Minimum is the lowest number required.

Maximum is the most allowed

Expressed 1.1 or 1.N or N.M

Object Identifier is the attribute or collection of attributes that the user wishes to use as the identifier of the object. It may be unique or not unique.

Attribute Domain is the description of values that an attribute may have.

size in characters

content type

range

list

Finding Objects. This done the same way as in E-R modeling - sorta. The source of the objects are the Use Cases.

Descriptions of usage provided by the users.

Input forms

Output forms

Worksheets

and such

 

Types of Objects

Simple Objects contain only simple attributes.

Composite Objects contain at least one composite attribute.

Compound Objects contain at least one object attribute.

Hybrid Objects contain combinations of the above.

Association Objects relate two objects.

Semantic Object Modeling is E-R Modeling without the connecting lines and drawn from Use Cases.

The Department of Public Works for a large city has decided to develop a "computerized" Pot Hole Tracking and Repair System (PHTRS).

Potholes are reported to the city. They to be entered by clerks into a database using computer screens. As potholes are reported, they are assigned an identifying number and stored by street address, size (on a scale of 1 to 10), location (middle, curb,..), district (determined from street address), and repair priority (determined from the size of the pothole).

When work is to be done on the potholes, clerks will enter data via a computer screen. Work order data are associated with each pothole and include pothole location and size, repair crew identifying number, number of people on crew, equipment assigned, hours applied to repair, hole status (work in process, repaired, temporary repair, not repaired), amount of filler material used, and cost of repair (computed from hours applied, number of people, material and equipment used).

Citizens may report damage done to vehicles by a potholes. A damage file is created to hold information about reported damage due to the pothole and includes citizen's name, address, phone number, type of damage, and dollar amount of the damage.

Build a Semantic Object Model.

A lesson in Civics

The U.S. Congress consists of two chambers [the house and the senate]. The house consists of members from each state based on the state’s population; each representing a district. Each member of the house stands election every two years. The senate consists of 100 members, two from each state. One third of the senate stands election every two years; the term of a senator is six years.

In each body, its members are assigned to committees, within each committee are sub-committees and working groups. Each committee has a chairman; as does each sub-committee.

Based on the following information define Semantic Objects, their attributes, their cardinality, and their linkages.

U.S. Rep. John E. Sununu

Sununu has been selected to serve on the House Appropriations Committee where he will hold seats on the Veterans Administration-Housing and Urban Development Subcommittee, the Treasury Postal Subcommittee, and the District of Columbia Appropriations Subcommittee. He also serves as a member of the House Budget Committee and as an at-large member of the Republican Policy Committee, which serves as the key mechanism for debate, development, and communication of issues and conference positions.

U.S. Rep. Charles Bass

Charles Bass, a Republican, represents the state's Second Congressional District, which includes the state's western and northern regions as well as Concord, Nashua, and a swath of the state's southern tier.

Bass is a member of the House Committee of the Budget, and serves as chairman on the Working Group of National Security and also on the Working Group on Social Security. He is also a member of the Committee on Transportation and Infrastructure, on which he serves on subcommittees handling aviation and surface transportation issues.

Bass is also a member of the House Permanent Select Committtee on Intelligence, on which he serves as a member of the Subcommittee on Human Intelligence, Analysis, and Counterintelligence.

U.S. Sen. Bob Smith

U.S. Senate, Republican. His term expires in 2002.

Smith is a member of the Armed Forces Committee and a member of the related subcommittees on Strategic Forces (chairman), Acquisition and Technology, and Seapower. Smith is also a member of the Environment and Public Works Committee, and serves on the Superfund, Waste Control, and Risk Assessment subcommittee (chairman) and the Transportation and Infrastructure subcommittee.

Smith is also involved in the Senate Government Affairs Special Investigation on Campaign Finance and serves as chairman of the Senate Select Committee on Ethics.

U.S. Sen. Judd Gregg

Republican. His current term expires in 2004.

His committee assignments include the Senate Appropriations Committee, on which he chairs the subcommittee that oversees the departments of Commerce, State, and Justice. He also serves on the appropriations subcommittees that oversee Defense, Foreign Operations, Labor-HHS-Education, and Military Construction. Gregg also serves on the Budget and the Labor and Human Resources committees.