MISMO_BIS MANAGEMENT INFORMATION SYSTEMS MODELING

Transcription

1 MISMO_BIS MANAGEMENT INFORMATION SYSTEMS MODELING Course code: IEZ001203W Grażyna Hołodnik-Janczura, Ph.D. K4/Z1 Operation Research, Finance, and Information System Engineering Division B-4, room 517 phone: (71) office hours on: Website: GHJ - PWR 1

2 CONDITIONS FOR RECEIVING CREDIT To receive credit a student must meet the following criteria: Lecture take two tests: min. 50% of score for each one first test: second test: Laboratory carry out the lab work achieve a score min. 50% deadlines: Part A: Part B: GHJ - PWR 2

3 MISMO_BIS BASED ON BARKER RICHARD AND CLIFF LONGMAN (CASE*MATHOD) CONTENTS I. Function Hierarchy Diagram (FHD) II. III. IV. Function Dependency Diagram (FDD) Entity Relationship Diagram (ERD) Basic technique of logical relational database design from an entity relationship model V. CRUD Method and Function Logic GHJ - PWR 3

4 Literature Basic literature Barker R., Longman C., CASE*Method: Function and Process Modelling, Addison-Wesley Pub. Comp., 1992 Barker R., CASE*Method: Entity Relationship Modelling, Addison-Wesley Pub. Comp., 1991 Additional literature Chen P.P., The entity-relationship modelling, ACM Transactions on Database Systems, 1976 Date C.J., An introduction to database systems, Addison-Wesley Pub. Comp., 1986 De Marco T. (1979) Structured analysis and system specification, Prentice Hall, Englewood Cliffs, NJ Flynn D.J., Fragoso Diaz O., Information Modelling, An International perspective, Prentice Hall, 1996 Gane C., Sarson T., (1989) Structured systems analysis: tools and techniques, Prentice Hall, Englewood Cliffs, NJ. GHJ - PWR 4

5 WHEN TO USE INFORMATION SYSTEMS MODELING TECHNIQUES? Project Planning Requirements Definition SDLC Waterfall Model FHD FDD ERD RDBD CRUD Techniques & Models Design Development Integration & Test Installation & Acceptance GHJ - PWR 5

6 LECTURE 1 Introduction Basic definitions Function Hierarchy Diagram Objectives of the function modeling Categories of function Business function definition Function decomposition Layout style patterns to illustrate the function hierarchy Approach in hierarchy modeling FHD example Summary Literature [Barker I] Barker R., Longman C., CASE*Method: Function and Process Modelling, Addison-Wesley Pub. Comp., 1992 GHJ - PWR 6

7 A KEY GOAL FOR US Obtaining detailed knowledge of the Structural Methods and Techniques for Management Information Systems Modeling Achieving practical skills in building these models focused on what the business really does need to achieve using relevant and appropriate functional modeling techniques Information models become a part of a specification of business requirements Information system modeling is a means, not an end enables to understand requirements, to plan and invent good system designs, and develop appropriate systems GHJ - PWR 7

8 MANY METHODS, MANY STANDARDS: TWO APPROACHES OF INFORMATION SYSTEMS DEVELOPMENT Traditional approach: structured methods developed which distinguished the functional approach from the data structured one Information Engineering (IE) Structured Systems Analysis and Design Method (SSADM) CASE*Method (Computer Aided Systems/Software Engineering) Yourdon Systems Method (YSM) Metodologica Informatica (MEIN) Modern approach: Object-oriented (OO) methods the technique of integrating processes and data into one object called Object Modeling Technique (OMT) Rational Unified Process (RUP) GHJ - PWR 8

9 MODELING TOOLS Software product modeling technique implementation with a different automation degree, which supports system requirements gathering, modification, publishing and prototyping. The highly advanced tools generate new deliverables, e.g. generate database design from an entity relationship model. CASE tools, e.g. IE Workbench, Designer 2000, Easy CASE, Architect. GHJ - PWR 9

10 MODEL DEFINITION The function of models in physics, biology, medicine and other sciences resembles that of myths as paradigms, or patterns, of the human world [Encyclopedia Britannica] A description or analogy used to help visualize something that cannot be directly observed [Merriam-Webster Online Dictionary] A construction model of a language must be able to identification of the model this is a precision condition A model may be expressed as A syntax some language (natural language) an algebraic formula (formal) a schema with rigorous standards and conventions (graphical) GHJ - PWR 10

11 META MODEL A meta model simply, is a model of a model [Barker I, s. 361] It s a definition of the construction model by the use of the language of this model It s created during a meta modeling process Designing CASE tools is an example of the meta modeling process GHJ - PWR 11

12 MODELING Modeling is an indispensable technique for presenting ideas, aiding understanding and predicting new ways of doing things Arguably our own perception of the world is an elaborate model we create in our brains from the information we have gathered Good modeling techniques are supported by rigorous standards and conventions to remove ambiguity GHJ - PWR 12

13 SCHEME OF THE PROCESS MODELING idea It s coming as a good understanding expressed by use individuality of the real world presented by symbol GHJ - PWR 13

14 IS BLACK BOX input (x) input information output (y) output information S relation S (x, y) models, procedures input (x) S output (y) GHJ - PWR 14

15 INFORMATION SYSTEM DEFINITION is a specific nervous system of an organization, which joins management system elements in a whole [Koźmiński A.] GHJ - PWR 15

16 INFORMATION SYSTEM A system is a named, defined and interacting collection of realworld facts, procedures and processes, along with the organized deployment of people, machines, various mechanisms and other resources that carry out those procedures and processes [Barker I, p. 162]. Information system is a part of an organization responsible for the development, operation and maintenance of computer-based systems [Barker I, p.369]. The ideal systems are a combination of manual and computer processes that elegantly fit into the way the business needs to run. GHJ - PWR 16

17 MANAGEMENT INFORMATION SYSTEM (MIS) Is a subset of the overall internal controls of a business covering the application of people, documents, technologies, and procedures by management accountants to solve business problems such as costing a product, service or a business-wide strategy. Management information systems are distinct from regular information systems in that they are used to analyze other information systems applied in operational activities in the organization. [O Brien, J (1999). Management Information Systems Managing Information Technology in the Internetworked Enterprise. Boston: Irwin McGraw-Hill] GHJ - PWR 17

18 FUNCTION MODELING TECHNIQUES 1. Function Hierarchy Diagram (FHD) 2. Function Dependency Diagram (FDD) 3. Detailed Function Definition Function Logic GHJ - PWR 18

19 OBJECTIVES OF THE FUNCTION MODELING Full, exact and accurate understanding of what organizations do To provide a model of functional needs of an organization, which will then act as a framework for development of new or enhanced systems The function modeling enables to understand requirements, devises good systems designs and creates appropriate systems is a means, not an end GHJ - PWR 19

20 OBJECTIVES OF THE FUNCTION MODELING (CONT.) To provide a model that is independent of any mechanism or processing method, allowing objective decisions to be made about alternative implementation techniques and coexistence with existing systems [Barker I, pp.1-2] GHJ - PWR 20

21 WHAT IS A MECHANISM? Mechanism a technique or technology for implementing a function: manual, telephone, computer, [Barker I, p. 369] The function Receive job request this could be done by , post, telephone, How the business carries out the function to achieve its objectives? What are new ways the function performs? is a mechanism The decision to choose the mechanism should be based on existing constraints, such as: people, organization, suitable technology, cost made during the design phase GHJ - PWR 21

22 BUSINESS FUNCTION DEFINITION Business function is an isolated and logically related group of activities Business functions in an organization are the way to achievement of their business objectives To achieve their of the business objectives is to be conditioned by permanent carrying out of business functions GHJ - PWR 22

23 BASIC GROUPS OF MANAGEMENT FUNCTIONS Planning: a formulation of objectives, a prediction of future conditions and resources Organizing: performing activities which would link various activities of many members of an organization Motivating: creating proper subordinates to tasks assigned to them Controlling: comparing performance or results of certain actions GHJ - PWR 23

24 CONDITIONS FOR BUSINESS FUNCTION CARRY OUT Relation with objectives Legislation (law) Corporate policy Role/job type, organization units Geographic location GHJ - PWR 24

25 FUNCTION HIERARCHY Hierarchy has a genealogical tree structure, sometimes similar to an organization structure The simplest and most useful technique for a startingpoint of business functions modeling is to produce a hierarchy of them, where each function is described by a simple unambiguous sentence, starting with a verb. GHJ - PWR 25

26 FUNCTION HIERARCHY DIAGRAM (FHD) FHD is a business functions model of an organization, these business functions are carried out agreement with their objectives and in the answer to events The function hierarchy is a result of n leveling decomposition top function (root) Every function type parent is described in more detail with the function type children GHJ - PWR 26

27 APPROACH IN HIERARCHY MODELING The full scope to modeling Bottom-up only The needs Missing information Top-down only Not needed details Top-down + Bottom-up The needs Missing details [Barker I, p. 56] GHJ - PWR 27

28 FUNCTION DECOMPOSITION Constructing a hierarchy from two different directions Function decomposition top-down plus function grouping bottom-up max 9 sub-functions at the same level General model: 2-3 levels Detailed model: 5-7 levels Creating hierarchy - iteration process GHJ - PWR 28

29 BASIC LAYOUT STYLE PATTERNS TO ILLUSTRATE FUNCTION HIERARCHY [BARKER I, PP ] a) vertical b) horizontal c) hybrid GHJ - PWR 29

30 ILLUSTRATION OF THE FUNCTION DECOMPOSITION [BARKER I, P. 57] function parent sub-function child These are all and only these functions which do need to carry out the parent function. The order of these functions implies no sequence Decomposition continuous until the required level of detail is achieved GHJ - PWR 30

31 CONSTRUCTION RULES OF A FUNCTION NAME Starting with a verb, adopt the same form through the hierarchy an imperative form is recommended It should continue with the object of the verb to things use a singular form It should be a full and descriptive text Include a condition in the full name for a function execute a conditional function Remove a mechanism: how the business carries out the function? Use a function label simply a short name or tag: a shot mnemonic or a number GHJ - PWR 31

32 Business function name components B. F. position in the hierarchy Label, reference code condition decomposition symbol F verb Take a delivery as per order noun - object function name graphic symbol GHJ - PWR 32

33 CATEGORIES OF FUNCTION Root function - is applied to function at the top of the hierarchy, this is a function of the highest level Leaf function is applied to functions at the bottom of the hierarchy and the analysis is still incomplete or complete Atomic function a leaf functions if the analysis is complete Elementary function a leaf functions if the analysis is complete and this function has to ensure that the information it manipulates remains consistent and coherent from the business perspective Elementary function may be broken up into atomic functions, which are not the only functions from the business perspective Common function a business function that appears in more than one place in the hierarchy GHJ - PWR 33

34 WHEN TO STOP FUNCTION DECOMPOSITION? An elementary function level ended decomposition Elementary function an end of decomposition from the business perspective GHJ - PWR 34

35 ELEMENTARY BUSINESS FUNCTION DEFINITION If started, it must be completed successfully or, if for some reason it can t be completed, any changes it makes up to the point of failure must be undone [Barker I, p. 40] It ensures that all changes to information representing the state of the business are correct and coherent before any of them are made available to another function It represented the state of the business The term elementary is not a property of the function, it applies to a position in a function hierarchy GHJ - PWR 35

36 CONCEPT OF THE ELEMENTARY FUNCTION ILLUSTRATION F 33 elementary function Transfer dollars from one bank account to another atomic function F331 Taking the money from one account F332 Putting the money into another account debit credit If the debit succeed (F331) but, for some reason, the credit fails (F332), than the bank s business is in an inconsistent state [Barker I, p. 136] GHJ - PWR 36

37 COMMON BUSINESS FUNCTIONS A business function that appears in two or more places in a hierarchy [Barker I, p. 114] Must: curry out the same functional processing, manipulate the same information in the same way (entity, attribute, relationship) have exactly the same decomposition The common functions are called: a master and the rest of them are a subordinate a master function may have more then one subordinate function, in practice they are not more than two, subordinate function can t be a master function for another subordinate function. GHJ - PWR 37

38 PRESENTATION OF THE COMMON BUSINESS FUNCTION Subordinate function P 55 P551 P2 Label of the master function P552 GHJ - PWR 38

39 CONCEPT OF THE COMMON FUNCTIONS ILLUSTRATION R11 Reserve seat on course R111 Check availability of seat on identified course R112 R12 Remove reservation from one to another R121 Delete carried out reservation R122 R11 GHJ - PWR Reserve seat on requested course R113 Inform and confirm reservation details R123 Reserve seat on course Calculate quota of remove reservation 39

40 FUNCTIONS WITH IDENTICAL DESCRIPTIONS ARE NOT COMMON Compare the detailed definitions of the common functions you may find that although they are not identical, they Set a task for an employee a function to produce a schedule for work Set a task for an employee a function to manage the personnel of an organization Each function manipulates the same or other information in a different way GHJ - PWR 40

41 COMMON FUNCTIONS - HAVE DIFFERENT DESCRIPTIONS It is more likely for two functions that are really common functions to have different descriptions, e.g. functions can be written from different viewpoints [Barker I, p. 117]: Allocate a class to a specified room for a regular slot during a term a function to produce a schedule for a class Allocate a room for use by a class at a regular time each week throughout a period a function to manage the resources of the college Each function manipulates the same information in the same way GHJ - PWR 41

42 REMOVING COMMON FUNCTIONS [BARKER I, P. 116] Modify the name of a function if necessary The lowest point in hierarchy which is parent to the common function Move to here GHJ - PWR Common functions 42

43 FUNCTION HIERARCHY DIAGRAM (FIRST AND SECOND OF LEVEL) MB Manage the transport business MAR EMP RES ACC TS Market service and promote the business M1 Recruit and maintain adequate personnel E1 Provide ticket sales and book seat R1 Provide finance A1 Plan and maintain adequate transport T1 M2 Analyze route usage Define and maintain crew schedule E2 R2 Sell ticket A2 Provide supplier accounting Create a transport plan for all routes T2 M3 Publish route Promote the service E3 Recruit personnel Provide staff training R3 Book seat Provide passenger check-in Produce report A3 Provide customer accounting Purchase a new transport Renovate old transport GHJ - PWR 43 T3

44 FUNCTION HIERARCHY DIAGRAM (THIRD OF LEVEL) E2 Recruit personnel E22 E23 E21 Make a job offer Analyze a job application Make a job interview E24 Select and accept applicant Book seat Accept a new booking Change one booking to another Accept withdrawal of booking GHJ - PWR 44 R2 R21 R22 R23

45 Function Hierarchy Diagram (fourth of level) E24 Select and accept applicant E241 E242 Review documents Negotiate job terms and conditions E243 Accept contract GHJ - PWR 45

46 THE KEY ISSUES Functions, what the organization has to do to achieve its objectives Unambiguous definition represents the essence of what the business does, as opposed to how it does it Independence from mechanism at the business level, functions should be defined in a manner that is independent of how they will eventually be carried out Attitude and quality the analyst must be objective, persuasive and educational, the models must be correct, useful and appropriate A means, not an end function modeling enables to understand requirements, devises good systems designs and creates appropriate systems GHJ - PWR 46

47 FHD SUMMARY Six interrogative words used in the research questions : What: what does and needs to do Why: relation with objectives Who: role/job titles When: sequence and timing Where: organization structure How: mechanism In a function hierarchy model only: what is an operation the business does, or needs to do why is the objective it is trying to achieve by doing it [Barker I, p. 80] GHJ - PWR 47