Normalization Exercise

from the picture, we can see ERD and make the table from it.



then, make 1NF and 2NF table with functional dependencies



Pegawai

• Nopeg -> Napeg,Tgllah,Umur,Alamat,Kdpos
• Nopeg -> Nobag
• Nopeg -> Bestempl

Bagian

• Nobag -> Nabag,Lokasi
• Nobag -> Pimpbag

Proyek

• Nopro -> Napro,Lokapr
• Nopro -> Nobag

however, kerja table and tanggungan table don't have to decomposition, because its a table of relation and dependency with no primary key.

then, 3NF functional dependency would be




reference :
NURAH AGUS SANJAYA ER, S.KOM,M.KOM. Slide ppt ke-6 : NORMALIZATION.

Normalization

database planning process
>collecting requirement of users or business
>developing E-R model based on requirement of users or business
>converting E-R model to collection of relation (table)
>normalization relatio for eliminating anomaly
>implementation of database with creating table for each relation that had normalization

database normalization
>normalization is forming process of database structure so most of ambiguity can be eliminating
>normalization stage started from lighter stage (1NF) to tighter stage(5NF)
>usually, only reaching at level 3NF or BCNF because its quite for producting tables in good quality
>why we do normalization?
>>>optimalizing of table structures
>>>increasing speed
>>>eliminating of the same input data
>>>more efficient in using storage
>>>decreasing redundancy
>>>avoid anomaly (insertion anomalies, deletion anomalies, update anomalies).
>>>increase data integrity
>a table told great (efficient) or normal if fulfilling 3 criteria, that is :
1. if there are decomposition table, so decomposition must guaranteed to be safe (Lossless-Join Decomposition). its mean, after the table was elaborated become new tables, that tale can relsulting the same previously table
2. looking after to depended of functional at data changes (Dependency Preservation).
3. not break the Boyce-Code Normal Form (BCNF)
>if third criteria (BCNF) cannot complete, at least the table ot break normal form third stage (3rd Normal Form/ 3NF)

functional dependency
>described connection of attributes in a relation
>an attribute told as functionally dependant inother if we using attribute value for determine another attribute value
>symsbol that used is for deputizing functional dependency that read as functional to determine.
>notation : A -> B
>>>A and B is attribute from a table. its means as functional A determine B or B depended in A, if and as if there are 2 row data with same A value, so B value can be same
>notation : A-/>B or Ax->B
>>>it is reverse from previously notatioen.
>example:

>>Functional Dependency:
>>>NRP -> Nama
>>>Mata_Kuliah, NRP -> Nilai
>>Non Functional Dependency:
>>>Mata_Kuliah -> NRP
>>>NRP -> Nilai
>functional dependency from value table is
>>>Nrp -> Nama, because for each value of Nrp is same, so name value same too
>>>{Mata_kuliah, NRP} -> Nilai, because value attribute depend on Mata_kuliah and Nrp as at same time. in other mean, for Mata_kuliah and Nrp that same, value will same too, because Mata_kuliah and Nrp was representing key (in unique characther)
>>>Mata_kuliah -> NRP
>>>NRP -> Nilai

first normal form - 1NF
>a table that told as first normal form if it not as unnormalized form table, where happen duplication of same kind field and possible for exist null field
>not be able for:
>>>multivalued attribute
>>>composite attribute or combination of both so price of attribute domain must atomic price.
>for example :
>>>data mahasiswa

>>>this tables not up to standard of 1NF
>>>decomposition become :


second normal form - 2NF
>2NF completed in a table if up to standard of 1NF, and all attribute except primery key, intactly have functional dependency on primary key
>a table not complete as 2NF if there are attribute that only have a partial functional dependency
>if there are attribute that not have dependency of primary key, so that attribute have to moved or eliminated
>functional dependency X -> Y told as complete if deleting a attribute A from X, that's mean Y not depend as functional anymore
>functional dependency X -> Y told as partial if deleting a attribute A from X, that's mean Y still depend as functional
>relation schema R in 2NF form if each attribute non primary key A is member of R depend on as complete as functional in primary key R
>example :this table complete 1NF, but not include as 2NF
>>>not complete as 2NF, because {NIM,KodeMk} assumed as primary key, while
{NIM, KodeMk} -> NamaMhs
{NIM, KodeMk} -> Alamat
{NIM, KodeMk} -> Matakuliah
{NIM, KodeMk} -> Sks
{NIM, KodeMk} -> NilaiHuruf
>>>that table need to decomposition become several table that p to standard 2NF
>>>the Functional dependency is:
{NIM, KodeMk} -> NilaiHuruf (fd1)
NIM -> {NamaMhs, Alamat} (fd2)
KodeMk -> {Matakuliah, Sks} (fd3)
>>>So :
fd1 (NIM, KodeMk, NilaiHuruf) -> Tabel Nilai
fd2 (NIM, NamaMhs, Alamat) -> Tabel Mahasiswa
fd3 (KodeMk, Matakuliah, Sks) -> Tabel MataKuliah

third normal form - 3NF
>3NF complete if have standard of 2NF form, and if there are no attribute non primary key that have dependency with other attribute non primary key (transitive dependensy)
>example :
>>>this table was up to standard of 2NF, but not complete as 3NF

>>>because there are still have an attribute of non primary key (viz, Kota and Provinsi) that have dependency with other attribute non primary key(viz, KodePos)
KodePos -> {Kota,Provinsi}
>>>until that table has to decomposition become Mahasiswa (NIM, NamaMhs, Jalan, KodePos) and KodePos (KodePos, Provinsi, Kota)

Boyce-Codd Normal Form (BCNF)
>BCNF has more powerful force and 3NF. for become BCNF, relation must in form of 1NF and each attribute forced depend on function at super key attribute
>for example : there are seminar relation, primary key is NPM + Seminar.
>case : student is able to take a or two seminar. each seminar need 2 counsellor and each studet guided by one of them. each counsellor only able to take one seminar. in this example, NPM and seminar showing a counsellor.

>sminar relation form is 3NF, but not BCNF because seminar code still depend with function on counsoller. if each counsellor has teach omly one seminar. seminar depend on one attribute that not super key as standardization as BCNF, so seminar relation must divided become two, that is :



4NF and 5NF
>relation is fourth normal form - 4NF, if relation in BCNF and no involved dependency multivalue. for eliminating dependency multivalue from one relation, we divide relation become two new relation. each relation containing two attribute that have multivalue connection.
>relation is fifth normal form - 5NF deal with property that known as join without losing information (lossless join). 5NF as known as PJNF or projection join normal form.this case is very rare emerge and difficult to detected practically

REFERENCE :
- NGURAH AGUS SANJAYA ER, S.KOM, M.KOM. Slide presentasi : Part 6 - DATABASE NORMALISASI

ER-Diagram

Database and ERD (Entity Relationship Diagram)
definition of database
- database is group of data that stored into magnetic disk, optical disk, or another secondary data storage.
- fused collection of datas, that connected mutually, from an enterprise (a company, firm, and government).

• manufacture company -> production planning data, actual production data, material ordering data, etc
• hospital -> data of patient, doctor, nurse, etc

DBMS (Database Management System)

- compilation of database with software application based on database

- the programs of application used for access and take care of database

- main purpose of DBMS is to provide an environment that easier and efficient for using, drawing and saving data and information.

definition of bit, byte, and field

- bit -> smallest part that have some value of 0 and 1

- byte -> collection of same bits

- field -> collection of same bytes as known as attribute

types of attribute

- single vs multivalue

• single -> only can containing mostly 1 value
• multivalue -> can containing more than 1 value with same kind value

- atomic vs composition

• atomic -> cannot divided into smaller attribute
• composition -> alliance of smaller attribute

- derived attribute -> attribute that can be yield from other attribute value, for example : age can be yield from attribute of birth datenull

- value attribute -> attribute with no value for a record

- mandatory value attribute -> attribute that must have a value
record or tupple
- a data row inside a relation
- consist of attribute collection which attribute interaction for advising entity or relation as detail
entiry or file
- file is collection of record that have same kind and same element, which the same attribute, but different data value.
- Type of file
In application process, file can be categorized as :

• Main file
• Transaction file
• Report file
• History file
• Protector file
• Activity file

Domain

- collection of value that can be inside one or more attribute.

- Each attribute in database relation defined as domain.

Element key of data

- Key is element of record that used for finding its in access time or can be used for identification each entity/record/row.

Types of key
- Superkey is one or more attribute that can be used for identification entity/record in table as uniquely (not all of attribute can be superkey).
- Candidate key is supperkey with minimal attribute. Candidate key cannot containing the attribute from other table, so candidate key already definite as superkey but not yet the other way.
- Primary key is one of candidate key that can be chosen or determined as primary key with 3 category, that is :

1. key is more natural for used as reference
2. key is more simple
3. key is guaranteed the unique

- alternate key is attribute from candidate key that not chosen as primary key

- Foreign key is any kind attribute that showing to primary key in other table. Foreign key happen in a relation that having cardinality one-to-many or many-to-one. Usually, Foreign key always put in table direct to many.
External key is a lexical attribute (or compilation of lexical attribute) that its value always identification one object instance.

ERD or Entity Relationship Diagram

- A model using word structure that saved in system as abstract,

- Difference between DFD and ERD

• DFD is a function network model that will executed by system
• ERD is data network model that emphasize in structure and relationship data.

The elements of ERD

- Entity

• Something exist inside real system or abstract system which data stored or where are the data.
• Symbolized as square of length. There are also line symbol as link between compilation of entity with entity and compilation entity with its attribute.

- Relationship

• Natural Relation happened between entity.
• Generally, given name with basic verb that facilitating for reading its relation.
• Symbolized as rhomb

- Relationship degree

• Account of entity that participated inside a relationship.
• Degree is often used in ERD\

- Attribute

• Characteristic of each entity or relationship
• Symbolized as circle

- Cardinality

• Showing maximal account tupel that can be relation with entity in the other one.

Relationship degree

- Unary relationship is Relationship model happen between the entity which coming from the same entity set.

- Binary relationship is relationship model happen between 2 entity.
- Ternary relationship between instance of 3 entity unilaterally.
Cardinality

- There are 3 cardinality relation, that is :

• One-to-one : relationship degree one-to-one expressed by one event in first entity, only have one relation with one event in second entity and on the contrary.
• One-to-many or many-to-one : relationship degree one-to-many is equal many-to-one dependent from where that relationship seen. For one event in first entity can have many relationship with event in second entity, the other way, one event in second entity only have relationship with one event in first entity.
• Many-to-many : happen if each event in an entity having a lot of relationship with event in other entity

Example : cardinality

reference :
- NGURAH AGUS SANJAYA ER, S.KOM, M.KOM. Slide presentasi : Part 5 - DATABASE DAN ER-DIAGRAM.

DFD(Data Flow Diagram) Quiz

Data Flow Diagram (DFD) describe division of system into smaller module. it is easier for user that not quite understand about computer to know how system works.

Context Diagram
> consist of a process and describing scope from a system
> the highest level from DFD that describing all input to system and output from system.
> system limited by boundary (that described with dash line)
> there is not be able to storage.

Zero Diagram
> describing process of DFD
> giving opinion totally about handled system, indicate function or main process that exist, data flow and external entity.
> in this level, enable for data storage.
> for unexplained process in next level ,then addicted symbol ‘*’ or ‘P’ in last number of process.
> balancing input and output between Zero diagram and context diagram must protected.

Detail Diagram
> the diagram that explaining what process inside zero diagram or next up level.
> number sequence level of DFD







> inside a level better not have more than 7 process and maximal 9, if more then must do decomposition.

Process Specification
> every process in DFD must have process specification
> in top level method that used for describing process with descriptive sentence
> in detail level that is in bottom process (functional primitive) requiring specification more structured.
> process specification can be guide for programmer in coding
> method that used in process specification: explain process in narrative, decision table, decision tree.

External Unity
> Something outside system, but its giving data into system or giving data from system
> symbol by box notation
> external entity not included as part as system
> giving name :
==> terminal name in the form of noun
==>terminal cannot have the same name, except the same object

Data Flow
> representing place stream of information
> described with straight line that connecting component from system
> data flow shown with arrow and line that given name as stream data flow
> data flow stream among process, data storage and showing data flow from data as input for system
> guidance of giving name :
==> name of data flow consist of some word stream connected with continue line
==> there is can’t be data flow that have same name and giving name must expressing its.
==> data flow consist of some element can be expressed with element group
==> avoid usage of word ‘data’ and ‘information’ for giving a name in data flow
==> as possible, the name of data flow fully written
> another rules :
==> the name of data flow enter into a process cannot same with the name of data flow that out from that process
==> data flow that in or out from data storage haven’t to given name if :
====> simple data flow and easier to understand
====> data flow describing all data item
==> there are can’t be data flow from terminal to data storage or on the contrary because terminal is not part of system, connection between terminal and data storage must pass process



Process
> process represented what system done
> process can turn data or input data flow into output data flow
> process functioning for transformation one or some input data become one or more output data appropriate with specification needed
> every process have one or some input and resulting one or some output
> process as known as bubble
> guidance of giving name process :
==> name process consist of verb and noun that expressing its function process
==> don’t using process word as part name a bubble
==> there is can’t be some process have the same name
==> process must given number. Number sequence as possible follow stream or process sequence. However number sequence can’t absolutely represented process sequence chronologically.

Data Storage
> represented existing data repository in system
> symbol with a couple of parallel line or two line with one of other side was open.
> process can taking data from or giving data to database
> guidance of giving name :
==> name must expressing data storage
==> if its name more that one word then must given continued sign

Symbol DFD


Data Dictionary
> function as helping system performer for interpreting application in detail and organizing all data element that used system precisely until user and system analyst having same basic knowledge about input, output, storage and process
> in analysis stage, data dictionary used as communication tools between system analyst and user
> in system planning stage, data dictionary used for make an input, report and database
> Data flow in DAD having global character, for more information can seen in data dictionary
> data dictionary loading the followings :
==> name of data flow: have to recorded in order to reader that needing more clarification about a data flow can easy to search
==> data form : used for grouping data dictionary into usage when system planning
==> data flow : showing where data streaming from and go.
==> clarification : giving explain about the meaning from data flow

Balancing inside DFD
> data flow that in into and out from one process must same with data flow that in into and out from process detailed in bottom level/standard
> the name of data flow that in into and out from one process must same with data flow that in into and out from process detailed
> amount and external entity name from a process must same with amount and external entity name from its process detailed
> things which must have to attention in DFD owning more than one level :
==> there is balancing input and output between one level and next level
==> balancing between level 0 and level 1 seen in input/output from data flow to or from terminal in level 0, while balancing between level 1 and level 2 seen in input/output from data flow to or from its process
==> name of data flow, data storage and terminal in each level must same if have same object

Prohibition inside DFD
> data flow mustn’t from external entity direct to other external entity without pass a process
> data flow mustn’t from data storage direct to external entity without pass a process
> data flow mustn’t from data storage direct to other data storage without pass a process
> data flow from one process direct to other process without pass a data storage better to / as possible avoided

reference:
> Slide PPT : Part 4 -DATA FLOW DIAGRAM, oleh : NGURAH AGUS SANJAYA ER, S.KOM, M.KOM

fourth Quiz

Requirement Analysis

INITIAL INVESTIGATION

System Investigation Concepts

Problem is gap between purpose of system and real condition of system, with any word, why system fail to reach their purpose of system that have definite before. to know everything that cause system fail analys better have to investigation before taking something to do for repair system. With investigation, an analys will more understand the problem and discussion

Many repair in detecting a problem may not real or not solved. It can be happen because :

a. purpose are too ideal

b. system can’t developed

c. system measuring not accurate

d. statement goal is dated

e. the gap between the ideal and the current system is temporary and will decrease given patience

in stage of problem solving, better to have study with :

1. describe system condition that have pass with detailed investigation activity
2. get the ideal system consensus
3. developing some alternative to decrease gap between ideal system and pass system
4. choose the best alternative and selling to the management

the aim of investigation is for stable or to show real problem that happen beside as a way an analys to understand deeply their system.

Constraint inside investigation system, is :

· Time, analys minus of time resources for cost

· Cost, related to the time of investigation, so there are limit cost

· Knowledge, system information manager ordered junior analys that not quite in knowledge to observe, so impact with investigation result that can be minus.

· Politics, management or other side propagate issues for obstruct investigation activity

· Interference, there are the other side wants to arrange in investigation activity that cause confesion

Recommendation

· Not take an action if there are no a problem

· Doing a protection with small problems

· Improving user capability or user skill in running or using information system.

· Allowing for modification totally system, so need idea to change it with a new system.

· Put a happen problem into system development plan.

Investigation tactics

– Listen, do not lecture

– do not presolve the problem

– compare stories

– look for reluctant responses

– probe for logical inconsistencies

– observe your effect

– expect hard, boring work

– avoid politics

investigation techniques, include activity of :

· direct internal probes, with 3 

technique direct investigation, there are :

o questionnaires

o interview

o observation

· indirect external probes, there are 

o procedure flow

o document review

o sampling

o Tabular tools

Description system nowadays, that explain 

a. inputs

b. outputs

c. files

d. data elements

e. transaction and action document volume

f. data flow diagrams

REQUIREMENT ANALYSIS

There are 4 goal to reach in this phase, that is

· Explain the system completely

· Describing the ideal system

· Taking the ideal system to nowadays system 

with take care of the problems

· Give support user conviction in 

system development team

The phase of requirement analysis are interaction 

phase intensive between analys and end-user where system development team use their skill to get reaction 

and trust from user, so can give good participation.

Method in requirement analysis

· interviews, 

· questionnaires, 

· observation, 

· procedure analysis, 

· document survey.

Sampling

Sampling can use for help decrease time and cost. 

to choose sample of population, there are need 

carefulness so will not fail.

Resources problem

· Time

· Money

· Skill

· Technology

· External factor

Requirement analysis document

· Analysis conduct

· User requirement

· Constraint system

· documentation

GENERATING SYTEMS ALTERNATIVES

Selection of strategic

– Distributed versus centralized processing

– Integrated versus dispersed databases

– Surround strategy of system development

Selection of tactics

· Now or later

o Technology

o Current cash

o Resources skill

o politic

· Change VS modification

· Configuration SLDC

Eight selection of operational planning

Selection of planning consist to 3 group, that is input, processing, and output. There are :

a. Input

   1. On-line versus off-line data entry.

   2. Keyed versus machine-readable data entry.

   3. Centralized versus decentralized data entry. 

b. Processing

   4. Batch versus real-time record update.

   5. Sequential versus direct access to records.

   6. Single versus multiple-user update of records.

c. Ouput

   7. Traditional versus turnaround documents.

   8. Structured versus inquiry-based reports.

SELECTING THE PROPER SYSTEM

Comparing tactic : the system is compared based on cost and profit according to relative.

It is 3 ways the A system can be says “more superior then other system” if:

Ø A have a lower cost than B, and have same profit

Ø A have a lower cost than B and higher profit then B

Ø Both of the system have same cost but A have higher profit than B.

Selling information system to 

the management as projected benefits 

has two problem, there are :

· Difficult to estimate quantity benefits

· If benefits estimated as quantity, 

rarely form in money 

Why important to translate become profit 

to measurable dollars? There are 3 reason :

· Company keep track money with 

traditional accountancy system

· Alternative information system compare 

with another alternative other area in company

· Top management decide to development system 

or not.

Cost Category

a. Hardware 

b. Software

c. People 

d. Supplies 

e. Telecommunications 

f. Physical site

Nature of costs

Comparing system information cost with system life, 

analys projecting how much changes cost for future. 

There 2 model cost operation system information :

a. Linear.

b. Exponential.

c. Step function.

Method for comparation system, there is:

a. Break-even analysis (BEP)

b. Payback period

c. Discounted payback period

d. Internal rate of return (IRR).

STUDI SISTEM

Problem statement

1. Nature of the problem detected 

(for example, increasing data entry backlogs).

2. How problem was detected 

(for example, customer complaints or 

performance measurement system).

3. Impact of problem on organizational goals 

(for example, delays processing of customer orders 

or reduces cash flow).

4. Departments and functions involved 

(for example, marketing department and 

order processing section of production department).

Existing system documentation

1. System function and interrelationships 

(this can be done with a graphic tools, 

such as a phyical data flow diagram, accompanied 

by step-by-step narrative description).

2. Processing volumes by type of document.

3. Processing times by type of document.

4. Bottlenecks (distribution of backlogs).

5. Organization policies affecting processing 

(example, a policy requiring that clerks process 

all commercial orders before residential orders).

6. Processing constraints.

   o People (for example, an average 20 percent 

       vacancy rate among data entry operators).

   o Hardware.

   o Software.

   o Development funds.

7. Organization of involved departments and 

function(for example,an organizational chart).

Problem correction alternatives

1. Procedure for generating information systems 

alternatives.

2. Cost determination for different alternatives.

3. Feasibility analysis.

   o Break-even years.

   o Payback years or discounted payback years.

   o Internal rate of return.

4. Qualitative factors.

5. Alternative recommended and why.

6. Alternative comparison with firm's goals 

(for example, ROI).

Recommended solution

1. Overall system description 

for recommended alternative.

2. New system functions and relationships 

(for example, logical data flow diagram).

3. Expected new system results.

   o Costs.

   o Benefits.

4. Proposed development schedule.

5. Development resource needs.

Docummentation

1. Physical and logical data flow diagrams.

2. Processing flow statistics 

(volume, timing, and so on).

3. Organizational charts.

4. Feasibility analysis details.

5. Development project schedule chart.

6. Development project proposed cost schedule.

Here are some guidelines for presenting the system study successfully :

· conduct short presentation

· reduce detail description technique

· represented clearly with visual tool

· bring workstation portable

· emphasized advantage from information system with a few existing alternative according to condition of atural company

Go / No-go decision

–        If the company decide to developmney the system,

then information department will do next process,

its a design process sistem.

– If not, the System Development Life Cycle (SDLC) 

will be stop.

– Frequently will be found problem with 

studying system and generally top management 

will ask to re-working with studying system

– Model will explain some stage part which 

repeat and sometimes information department

will make decision repeating the stage before 

explain studying system

– With alternative, decision for repeating 

a SDLC stage previously or not is called 

Go – No –Go Decision

Reference:

• Slide PPT Pengamatan Awal, Kebutuhan Analisis; Ngurah Agus Sanjaya ER, S.KOM, M.KOM
• http://kuliah.dinus.ac.id/ika/asi.html

Third Quiz in ADSI

System Development

System development can be interpreted as compilation of new system for replacing the all of old system or repairing the existing system.

The important of system development is :

• Existence of problems at the old system, that can be the form of

• An error
• Growth of Organization
• To reach for the opportunity
• Existence of instructions from directives

The purpose of system development

• To resolving the existence of problems
• Reach for the opportunity
• Fulfilling the existence of instructions

The organization’s expectation after implementing an information system

After developing the system, the expectation is upgrading level connected with

• Performance. Upgrading the result of job activity in new system, until its more effective. Performance can be measured from throughput and response time.
• Information. Upgrading of information quality that given.
• Economy. Upgrading in benefit or advantages or decreases cost happen.
• Control. Upgrading in control for detection and repairing the mistakes that happen.
• Efficiency. Upgrading of operation efficiency.
• Services. Upgrading of service that given by system.

The principles of developing an information system

• Developed system is management
• Developed system is big capital investment by considering to
• investigation of all the alternatives
• the best investment has to valuable
• Developed system is require an educated people
• Activity step and duty must be conducted in the process of system development
• the process of system development doesn’t have in sequence
• don’t afraid to canceled the project
• the documentation has to be performed to guidance in system development

There are many of system development life cycle models. three of them is

1. Waterfall model

The waterfall model is a sequential development process, in which development is seen as flowing steadily downwards (like a waterfall) through the phases of Conception, Initiation, Analysis, Design (validation), Construction, Testing and maintenance.

The first formal description of the waterfall model is often cited to be an article published in 1970 by Winston W. Royce (1929–1995). In Royce's original waterfall model, the following phases are followed in order:

To follow the waterfall model, one proceeds from one phase to the next in a purely sequential manner. For example, one first completes requirements specification, which are set in stone. When the requirements are fully completed, one proceeds to design. The software in question is designed and a blueprint is drawn for implementers (coders) to follow — this design should be a plan for implementing the requirements given. When the design is fully completed, an implementation of that design is made by coders. Towards the later stages of this implementation phase, disparate software components produced are combined to introduce new functionality and remove errors.

2. Iterative and incremental development

Iterative and Incremental development is a cyclic software development process developed in response to the weaknesses of the waterfall model. It starts with an initial planning and ends with deployment with the cyclic interaction in between.

Incremental development is a scheduling and staging strategy, in which the various parts of the system are developed at different times or rates, and integrated as they are completed. It does not imply, require nor preclude iterative development or waterfall development - both of those are rework strategies. The alternative to incremental development is to develop the entire system with a "big bang" integration.

Iterative development is a rework scheduling strategy in which time is set aside to revise and improve parts of the system. It does not presuppose incremental development, but works very well with it. A typical difference is that the output from an increment is not necessarily subject to further refinement, and its testing or user feedback is not used as input for revising the plans or specifications of the successive increments. On the contrary, the output from an iteration is examined for modification, and especially for revising the targets of the successive iterations

3. Spiral model

The spiral model is a software development process combining elements of both design and prototyping-in-stages, in an effort to combine advantages of top-down and bottom-up concepts. Also known as the spiral lifecycle model, it is a systems development method (SDM) used in information technology (IT). This model of development combines the features of the prototyping model and the waterfall model. The spiral model is intended for large, expensive and complicated projects.

The steps in the spiral model can be generalized as follows:

1. The new system requirements are defined in as much detail as possible. This usually involves interviewing a number of users representing all the external or internal users and other aspects of the existing system.
2. A preliminary design is created for the new system.
3. A first prototype of the new system is constructed from the preliminary design. This is usually a scaled-down system, and represents an approximation of the characteristics of the final product.
4. A second prototype is evolved by a fourfold procedure:
1. evaluating the first prototype in terms of its strengths, weaknesses, and risks;
2. defining the requirements of the second prototype;
3. planning and designing the second prototype;
4. constructing and testing the second prototype.

Approaches of developing a system

There are several approach for developing a system, that is :

- Looked into the methodology that used is

- Classical approach. This methodology approach, developing system with following the steps in system life cycle, is approach inside system development by following adequate technique.

- Structured approach. This methodology approach, basically trying to provide to the system analysis addition of tools and techniques for developing the system beside remain to follow idea of system life cycle.

- Looked into the reached target

- Piecemeal Approach, is approach system development emphasize to an event or application.

- Systems Approach, observe information system as an integrated unity for each event or application.

- looked into the way of determining requirement of system :

- Bottom Up Approach, started from low level organization, that is operational level where the transaction done.

- Top-down approach, started from high level organization, that is strategic planning level.

- looked into how to developing:

- Total-system approach, is approach developing system totally at once time.

- Modular approach. this approach try to breaking complicated system into some simple part or module, so the system is easier to understand and developed.

- looked into the technology that used is :

- Great Loop Approach, applying all change at once time with using sophisticated technology.

- Evolution Approach, applying sophisticated only for applications just needing at that moment and will developing for next periods following the requirements according to growth of existing technology.

the meaning of methodology, method and algorithm is :

• Methodology is methods unit, procedures , job concepts , rules, and postulates that used for a knowledge, art, or other discipline.
• method is a manner or systematic technique to do something.
• Algorithm is the sequence procedure that given by a methodology for resolving the problem.

Methodologies of system development classified become three group :

1. Functional Decomposition Methodologies. This methodology is emphasize in system solver into smaller subsystems, until it is easier to understand, planning and implementation.

2. Data Oriented Methodologies. This methodology is emphasize in characteristic of data that would have proceed. This methodology separate become two class, that is :

• Data-flow oriented methodologies. Generally, This methodology based on system solver into modules that based on the type of data element and behavior of its module logic inside the system.
• Data-structured oriented methodologies. This methodologies has emphasize structure from input and output in system. Then, this structure will used as basic structure from its system. Function relational between module or system elements explained from the structure system.

3. Prescriptive Methodologies

Included this methodologies is :

• ISDOS, is developed software by university of Michigan. The ability of ISDOS is automatic the process of development system.

• PLEXSYS. The ability of PLEXSYS is to do transformation a language of high level computer language into an executable code for a configuration the hardware that expected.

• PRIDE offered by a company in united state, that is M. Bryce & Ass. Pride is a great compilation software for analysis or design structured system, management data, project management and documentation.

• SDM /70 or Systems Development Methodology /70 developed and propagated by a company in united state. This methodology is a software that has content with collection of method, estimation, documentation, and administration instruction for helping user to developing and take care of system

• SPECTRUM
• SRES and SREM

tools for developing a system can be :

1. Graph, that is : HIPO, DFD, SADT, W/O, JSD

2. Chart, that is : activity charting (systems flowchart, program flowchart, paperwork flowchart or called as for flowchart, database relationship flowchart, process flowchat, gantt chart), layaout chating, and personal relationship charting.

there are many techniques used in developing a system :

• project management techniques, that is : CPM (critical path method) and PERT(Program Evaluation and review technique) . This technique used for project scheduling.
• fact finding techniques, technique that can used for collecting the data and finding facts in learning event the exist system. this techniques include : interview, observation, questionnaires, sampling.
• cost-effectiveness analysis (or cost-benefit analysis)
• meeting perform technique
• walkthrough

the differences of being a system analyst and a programmer and also mention what are the knowledge a system analyst should posses

System analyst is the person who analyzing system (learn how the problems arise and determining requirements user of system) for identification possible resolving. Otherwise, a programmer is person create the program code for an application pursuant to building design which have been made by system analyst.

The knowledge a system analyst should posses is :

• Knowledge about data processing technique, computer technique, and computer programming.
• General Knowledge of business
• Knowledge about the quantitative method
• Ability in trouble-shooting
• Ability in communication between personal
• Ability in constructing relation between personal.

reference :

• Prof. Dr. Jogiyanto HM, MBA, Akt. 2005. ANALISIS & DESAIN SISTEM INFORMASI : Pendekatan Terstruktur, Teori dan Praktik Aplikasi Bisnis. Yogyakarta : Penerbit Andi.
• www.klasiber.net/file.php/1/PSI_I.pdf
• http://en.wikipedia.org/wiki/Waterfall_model
• http://en.wikipedia.org/wiki/Iterative_and_incremental_development
• http://en.wikipedia.org/wiki/Spiral_model