A Quick Review of Analysis

Stages of the Systems Development Life Cycle Planning Analysis Design Construction

Modeling A model is a representation of reality Systems analysts try to understand a business by drawing “pictures” or models of the business and its workings. Three primary types of models: (1) activity models, (2) data models, and (3) interaction models

Business Modeling In Planning and Analysis: An Overview of the MIS Approach Data Model Activity Models Interaction Models Systems Design ERD FHD, PM PLD, ELC

Analysis Tasks with REAL Interaction Modeling Systems Design Activity Analysis Interaction Analysis 1 Interaction Analysis 2 PLD, ELC FHD, PM REA Data Analysis ERD

Types of Models Activity models: Records the activities of interest to the business (i.e., the things the business does or should do) Involves decomposition of business processes from the highest level (AMP of Resources, Conversion Processes, MSC Processes) to the lowest (elementary processes) Also involves the specification of process dependency events, to refine decomposition of the processes

HEART OF ORGANIZATION Conversio n Processes Customers Finished Goods and Services to Customers MSC Processes Supply goods and services Receive payment Activity Models: Template for Decomposition of Business Processes (IPSO) Suppliers AMP Processes Input Resources to the Organization Request input resources Pay for input resources Adds value RBMS Source: Hollander, Denna & Cherrington (2000), adapted

Business Processes AMP Processes Human Resources Financial Resources Supplies Inventories Property, Plant and Equipment Conversion Processes Operations Varies widely depending upon the industry MSC Processes Marketing Sales Collection and Credit

Business Process: Simple MS Process and Events Ship goods Take customer order

Figure 6 FHD: Partial Business Function Decomposition

Types of Models Interaction models: Define how things the business does (activities/events) affect things of interest to the business (data) Faculty at OU have combined the IE notation of an interaction model with the accounting REAL model Formal interaction modeling facilitates the transition from systems analysis to systems design.

REAL Model of A Business Event: The Event and Surrounding RALs What happened? - event When did it happen?- sequence Who was involved?-agents What resources were involved? – resource(s) Where did it occur? – loc. Event Internal Agent Resource External Agent Location Source: Hollander, Denna & Cherrington, 1996

REAL modeling is an aid in analyzing an organization and its activities (helps develop activity models by identifying lowest level of decomposition) Helps decide what data to collect (helps develop data models) Enhances your ability to evaluate business processes

REA Template With Two Events Resource Internal Agent External Agent External Agent Location Event 1: Take customer order Internal Agent Resource Event 2: Ship goods Event 2: Ship goods Location External Agent External Agent

Business Rules Narrative descriptions of policies, procedures, or principles in an organization Simple Examples: –Each purchase order must have only one vendor –Each vendor may have one or more purchase orders

Relationships Data modeling term that indicates an association between tables: How the things of significance are related (A FK must match to an existing PK, or else be NULL) This controlled redundancy allows linking of tables (hence “relational”) Entity-Relationship Diagram (ERD): A data model (at the conceptual level) that shows the relationships enforcing business rules between entities (tables) in a database environment

Connectivity or Cardinality One-to-One (PK ---> PK) - Generally indicates that your data model has two entity types that can be collapsed into one One-to-Many (PK ---> FK) - Most common Many-to-Many (FK ---> FK) - Not enforceable by RDMS; generally indicates that a modeling error has occurred - this type of relationship means that your model is missing an entity type

Cardinality of Relationships Mandatory - an instance of an entity in one table does require a associated record in another table (as defined by a relationship) Optional - an instance of an entity in one table does not require a associated record in a another table (as defined by a relationship)

Validate The REAL Model With Business Persons Those who understand the details and objectives of the business process and events being modeled should perform the validation. Validation sessions should result in either the confirmation of the model’s accuracy or modification of the model.

Events Most events are easy to identify because the business records data on forms or files. Events are characterized by the fact that they happen or have duration –For activity and REAL models, they are characterized by at least a verb and a noun, but could have an adjective, take customer order, deliver customer order, pay supplier –For data models (converting REAL to ERD), they are characterized by a noun, e.g., Order header, Order detail, Sales header, Sales detail, Cash receipt

Surrounding RALS RESOURCES Entity types that describe tangible things. EQUIPMENT, INVENTORY, CASH, MACHINE, MATERIAL, PART, PRODUCT, VEHICLE, but they can also be Informational Resources, e.g., PRODUCT CATALOG

Surrounding RALs AGENTS Entity types that describe roles played in a system. They usually represent people or organizations. APPLICANT, BORROWER, CLIENT, CREDITOR, EMPLOYEE, EMPLOYER, INSTRUCTOR, MANAGER, SALESPERSON, VENDOR

Surrounding RALs LOCATIONS Entity types that describe locations BRANCH, BUILDING, CAMPUS, CITY, COUNTRY, COUNTY, SALES REGION, WAREHOUSE, STORE, FRANCHISEE

A REAL Interaction Model for MSC Function Sell Goods Customer Inventory Salesperson Department Receive Payment Cashier Cash Store

Types of Models Data model: One type is the ERD that depicts data (entities, attributes) and the relationships enforcing business rules between entities. The primary goal is to accurately portray the fundamental elements of the business information system. The data model is implemented as a database in a developed system (central to the IS)

ERD with Normalization