Business System Analysis and Design Notes

*ISarrangement of people,data, surgical deales, training technology that interact to collect, mathematical process,provide as output the info readed to support the organization. Types of IS TPS,MIS,decision support clay, communions and collaboration corpse,expert system, office automation system & executive director info systemTypes of Stakeholders carcass owners (middle and executive managers, supervisors),System usancers (clinical& service ploughers,technical and professional workers suppliers,customers,employees),System Builders (network admin,security admin,data base programmer,system programmer),System Designers (web archs,graphic artists,network architectures),External service provider (sales engineers, technology engineers, system consultants),Project manager,System psychoanalystis a problem solver,he/she studies craft probs and opportunities,then trans hurl them into info that bequeath be utilize by technical specialists.System analystspecialist who studies problem s and need of an organization to determine how people,data,processes and info technology contribute best compass improvements for the mercenary enterprise. Skills by System AnalystWorking knowledge of information technology(The analyst essential be aw be of both(prenominal) existing and emerging information technologies),Computer programming, experience and expertise,General byplay knowledge,General problem-solving skills,Good interpersonal communication skills,Good interpersonal relations skills,Flexibility and adaptability,Character and ethics. information sys architectureprovides a foundation for organizing various components of any info sys you distribute to develop. a unifying framework into which various stakeholders with different perspectives stinkpot steer and determine the fundamental building blocks of information systems. Views of knowledge System owners view Interested not in raw data but in information. (Business entities and business rules) System usersvi ew View data as something save on forms,stored in file cabinets,recorded in books and spreadsheets,or stored on computer.Focus on business issues as they pertain to data. info requirement System designers view Data structures,database schemas,fields,indexes,and constraints of particular database management system (DBMS). System builders view SQL,DBMS or otherwise data technologies Views of process System ownersviewConcerned with high-level processes called business functions.A cross-functional information system System usersviewConcerned with work that must be performed to provide the appropriate responses to business events. Business processes,Process requirements,Policy,Procedure, Work prey System designersviewConcerned with which processes to automate and how to automate them. Software specifications System buildersviewConcerned with programming logic that implements automated processes. Application program,Prototyping Views of communication System owners view Who? Where? Wh at?System users view Concerned with the information systems inputs and outputs. System designers view Concerned with the technical design of both the user and the system-to-system communication interfaces. System builders view Concerned with the construction, installation, testing and death penalty of user and system-to-system interface solutions *Basic principles of system nurture Get the system users involved. Use a problem-solving approach. Establish phases and activities. Document with development. Establish standards.Manage the process and projects. Justify systems as capital investments. Dont be agoraphobic to cancel or revise setting. Divide and conquer. Design systems for growth and change. The need to improve Performance Info Eco/controlcosts Control/Security Efficiency supporter Phases for system development scope definition, problem analysis, requirements analysis, formal design, decision analysis, fleshly designand integration, construction and testing, installat ion and delivery. Cross life-cycle activity Fact-finding, Documentation and presentation Documentation, Presentation, Repository), feasibleness analysis, Process and project management Routes through the basic systems development phases stick driven development strategies (process, data, object mildew), Rapid application development (RAD), commercial application package implementation, system maintenance *Benefits of use case standarding Provides tool for capturing functional requirements. Assists in decomposing system into manageable pieces. Provides means of communication with users/stakeholders concerning system functionality in language they understand.Provides means of listing, assigning, tracking, controlling, and management system development activities. Provides aid in estimating project scope, effort, and schedule. The affinitys that can appear on a use-case model diagram Use case association relationship, extension use case, abstract use case, depends on, inheritance Use case a behaviorally related to sequence of steps (scenario), both automated and manual, for the purpose of completing a bingle business task.Steps for preparing a use-case model expose business actors. Identify business use cases. Construct use-case model diagram. Documents business requirements use-case narratives *Data modeling(database modeling)a technique for organizing and documenting a systems data. Data positioning ConceptsEntity(class of persons, places, objects, events, or concepts about which we need to capture and store data),Attribute(descriptive property or typical of an entity.Synonyms include element, property and field), Data type(property of an attribute that identifies what type of data can be stored in that attribute),Domain(a property of an attribute that defines what nurses an attribute can legitimately take on),Default value(the value that will be recorded if a value is not specified by the user),Key(an attribute, or a base of attributes, that assu mes a unique value for each entity instance. It is sometimes called an identifier),Subsetting criteria(an attribute whose exhaustible determine divide all entity instances into useful subsets.Sometimes called an inversion entry),Relationship(a natural business association that exists surrounded by one or more entities),Cardinality(the minimum and maximum number of occurrences of one entity that may be related to a single occurrence of the other entity),Degree(the number of entities that participate in the relationship),Recursive relationship(a relationship that exists between instances of the same entity),Foreign chance on(a primary key of an entity that is utilise in another entity to identify instances of a relationship),Parent entity(a data entity that contributes one or more attributes to another entity, called the child.In a one-to- many an(prenominal) relationship the parent is the entity on the one side),Child entity(a data entity that derives one or more attributes fro m another entity, called the parent.In a one-to-many relationship the child is the entity on the many side),Nonidentifying relationship(relationship where each participating entity has its own independent primary key), Identifying relationship relationship in which the parent entity key is also part of the primary key of the child entity,Generalization(a concept wherein the attributes that are common to several types of an entity are sort into their own entity),Nonspecific relationship(relationship where many instances of an entity are associated with many instances of another entity.Also called many-to-many relationship) ,Sample CASE lance Notations Entity relationship diagram (ERD)a data model utilizing several notations to depict data in terms of the entities and relationships described by that data. Logical Model Development Stages1Context Data model(Includes only entities and relationshipsTo establish project scope). 2Key-based data model(Eliminate nonspecific relationships Add associative entitiesInclude primary and alternate keysPrecise cardinalities). to the full attributed data model(All remaining attributesSubsetting criteria). 4Normalized data model Normalize a logical data model to remove impurities that can make a database unstable, inflexible, and nonscalable. archetypal normal form (1NF)entity whose attributes behave no more than one value for a single instance of that entity,Any attributes that can have multiple values actually describe a separate entity, possibly an entity and relationship.Second normal form (2NF)entity whose nonprimary-key attributes are dependent on the full primary key,Any nonkey attributes dependent on only part of the primary key should be moved to entity where that partial derivative key is the full key,May require creating a new entity and relationship on the model. Third normal form (3NF)entity whose nonprimary-key attributes are not dependent on any other non-primary key attributes. *Modelpictorial representati on of reality.Logical modelnontechnical pictorial representation that depicts what a system is or does. forcible modeltechnical pictorial representation that depicts what a system is or does and how the system is implemented Process modelinga technique used to organize and document a systems processes. (Flow of data through processes,Logic,Policies,Procedures) Data merge diagram (DFD)a process model used to depict the decrease of data through a system and the work or processing performed by the system.Synonyms are bubble chart, transformation graph, and process model. The DFD has also become a popular tool for business process redesign. Processes on DFDs can operate in parallel (at-the-same-time). DFDs show the flow of data through a system. Processes on a DFD can have dramatically different timing (daily, weekly, on demand) Context data flow diagrama process model used to document the scope for a system. Also called the environmental model. Think of the system as a black box. 2A sk users what business transactions the system must respond to. These are inputs, and the sources are external agents. 3Ask users what responses must be produced by the system. These are outputs, and the destinations are external agents. 4Identify any external data stores, if any. 5Draw a context diagram. bunk diagrama tool used to depict the decomposition of a system. Also called hierarchy chart.