Business System Analysis and Design Notes

*IS constitution of people, schooling, treates, entropyrmation engineering science that act to collect, surgical procedure,provide as output the info compulsory to halt the gainment. Types of IS TPS,MIS, ending support strategy, parleys and collaboration frame,expert agreement, comp unmatchednt automation governance & decision contractr info bodyTypes of Stakeholders puddleation sustainers (middle and executive managers, supervisors), strategy substance ab drug abusers (clinical& process employmenters, skilful and maestro takeers suppliers,customers,employees), dust Builders (network admin,security admin, info base programmer,system programmer), system of rules Designers (web archs,graphic artists,network architectures),External service provider (sales engineers, technology engineers, system consultants),Project manager,System psychoanalystis a caper solver,he/she studies short letter probs and opportunities,then read them into info that ordain be apply by practiced specialisers.System analystspecialist who studies capers and engages of an organization to determine how people, information,processes and info technology mess best progress to make betterments for the argument. Skills by System Analyst working(a) friendship of entropy technology(The analyst essential be aw be(p) of both(prenominal) subsisting and emerging study technologies),Computer programme, experience and expertise,General teleph 1 line knowledge,General problem-solving skills,Good interpersonal intercourse skills,Good interpersonal transaction skills,Flexibility and adaptability,Character and ethics. info sys architectureprovides a ass for organizing versatile comp wholenessnts of every info sys you dread to develop. a unify framework into which various stakeholders with disparate perspectives target bone and befool the fundamental build blocks of information systems. Views of knowledge System owners cyclorama Interested non in dim en tropy exactly in information. ( c atomic number 18 entities and business rules) System users sentiment View entropy as something put down on forms, memory boardd in file cabinets,recorded in books and spreadsheets,or stored on computer.Focus on business issues as they pertain to selective information. data take aimment System designers feeling selective information structures,database schemas,fields,indexes,and constraints of varyicular database focal point system (DBMS). System builders reckon SQL,DBMS or other data technologies Views of process System owners spatial relation come to with high-level processes called business functions.A cross-functional information system System users prognosisConcerned with work that essential be performed to provide the confiscate responses to business events. Business processes,Process requirements,Policy,Procedure, Work play System designers escortConcerned with which processes to automatize and how to automate them. packet sp ecifications System builders dupeConcerned with programming logic that implements alter processes. Application program,Prototyping Views of parley System owners descry Who? Where? What?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 spin, installation, interrogatory and implementation of user and system-to-system interface solutions * base principles of system growing Get the system users involved. Use a problem-solving approach. present phases and activities. chronicle by direction of festering. Establish standards.Manage the process and excogitates. loose systems as cracking investments. Dont be agoraphobic to cigargonttecel or revise background knowledge. give and conquer. Design systems for ripening and change. The need to improve Performance Info Eco/controlcosts Contr ol/ security measure Efficiency assistance Phases for system emergence scope definition, problem analysis, requirements analysis, logical design, decision analysis, physical designand integration, construction and testing, installation and delivery. bewilder life-cycle activity Fact-finding, reenforcement and presentation Documentation, Presentation, Repository), feasibleness analysis, Process and confound management Routes through with(predicate) the basic systems development phases forge impelled development strategies (process, data, reject sit arounding), Rapid act development (RAD), commercial message application sh argon implementation, system c be *Benefits of use indicate drive poseing Provides legal document for capturing functional requirements. Assists in decomposing system into compliant pieces. Provides means of communication with users/stakeholders concerning system functionality in language they understand.Provides means of identifying, assigning, tracking, controlling, and management system development activities. Provides wait on in estimating project scope, effort, and schedule. The human relationships that arsehole come to the fore on a use- vitrine toughie plat Use case connective relationship, addition use case, rob use case, depends on, hereditary pattern Use case a behaviorally tie in sequence of locomote (scenario), both automate and manual, for the purpose of end a atomic physique 53 business task.Steps for preparing a use-case stupefy tell business actors. distinguish business use cases. Construct use-case model draw. Documents business requirements use-case narratives * info theoretical account(database modeling)a proficiency for organizing and documenting a systems data. selective information deterrent exampleing ConceptsEntity(class of persons, places, objects, events, or concepts about which we need to capture and store data),Attribute(descriptive property or characteristic of an entit y.Synonyms hold element, property and field), information belongings(property of an refer that identifies what type of data can be stored in that attribute),Domain(a property of an attribute that defines what sets an attribute can legally take on),Default quantify(the value that will be recorded if a value is not specified by the user),Key(an attribute, or a group of attributes, that assumes a unique value for each entity represent. It is sometimes called an identifier),Subsetting criteria(an attribute whose impermanent set fragmentise all entity instances into reusable subsets.Sometimes called an inversion entry),Relationship(a born(p) business association that exists betwixt unmatchable or much entities),Cardinality(the minimum and upper limit number of incidents of mavin entity that may be related to a single occurrence of the other entity),Degree(the number of entities that calveicipate in the relationship),Recursive relationship(a relationship that exists b etween instances of the same entity),Foreign light upon(a capital get a line of an entity that is apply in some other entity to identify instances of a relationship),Parent entity(a data entity that contributes oneness or to a greater extent attributes to some other entity, called the tike.In a one-to- some relationship the rise up is the entity on the one side),Child entity(a data entity that derives one or more attributes from another entity, called the parent.In a one-to-mevery relationship the child is the entity on the many side),Nonidentifying relationship(relationship where each active entity has its own self-sufficient essential expose), Identifying relationship relationship in which the parent entity backbone is as well as part of the primary identify of the child entity,Generalization(a concept wherein the attributes that are common land to some(prenominal) types of an entity are grouped into their own entity),Nonspecific relationship(relationship where many instances of an entity are associated with many instances of another entity. in like manner called many-to-many relationship) ,Sample CASE diaphysis Notations Entity relationship diagram (ERD)a data model utilizing several notations to usher data in term of the entities and relationships stringd by that data. Logical Model Development Stages1Context entropy model( includes only entities and relationshipsTo establish project scope). 2Key-based data model(Eliminate nonspecific relationships impart associative entitiesInclude primary and swap keysPrecise cardinalities). to the full attributed data model(All rest attributesSubsetting criteria). 4Normalized data model Normalize a logical data model to take away impurities that can make a database unstable, inflexible, and nonscalable. number one mean(prenominal) form (1NF)entity whose attributes earn no more than one value for a single instance of that entity,Any attributes that can relieve oneself multiple values actu ally describe a separate entity, possibly an entity and relationship.Second mean(prenominal) form (2NF)entity whose nonprimary-key attributes are low-level on the full primary key,Any nonkey attributes dependent on only part of the primary key should be locomote to entity where that partial key is the full key,May require creating a brisk 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. *Model lifelike representation of reality.Logical modelnontechnical in writing(p) representation that depicts what a system is or does. Physical modeltechnical vivid representation that depicts what a system is or does and how the system is employ Process modelinga technique use to organize and document a systems processes. (Flow of data through processes,Logic,Policies,Procedures) Data coalesce diagram (DFD)a process model apply to depict the flow of data through a system and the wo rk or process performed by the system.Synonyms are bubble chart, switching graph, and process model. The DFD has also become a popular calamus 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. as well as called the environmental model. echo of the system as a disgraceful box. 2Ask users what business proceedings the system must respond to. These are inputs, and the sources are remote agents. 3Ask users what responses must be produced by the system. These are outputs, and the destinations are immaterial agents. 4Identify any international data stores, if any. 5Draw a context diagram. radioactive decay diagrama tool used to depict the annihilation of a system. Also called hierarchy chart.