diPta_oN_bLoG

Exercise

2009-05-03T04:21:00.000-07:00

ERD

From ERD diagram I found there are two error:
• There have no cardinality between entity BAGIAN and PROYEK.
• There have no relation from entity PROYEK to ternary, because table PROYEK has have relation KERJA with table PEGAWAI.

I draw ERD to make easier to listen:
ERD

MAPPING
NORMALISASI
1NF and 2NF

For table TANGGUNGAN and KERJA have no primary key,,so I do not normalism that sesion.
For the 3NF normalization. First, determine attribute from above which have transitive dependency, that is:

Database Normalization

2009-04-25T22:27:00.000-07:00

In the field of relational database design, normalization is a systematic way of ensuring that a database structure is suitable for general-purpose querying and free of certain undesirable characteristics—insertion, update, and deletion anomalies—that could lead to a loss of data integrity.

The reason is other waste storage space (hard disk),Normalization process is the establishment of database structure so the ambiguity can be removed. Normalization stage, starting from the most mild (1NF) to most stringent (5NF). Normalization is usually only up to the level of 3NF or BCNF because already sufficient to generate the table-a table of good quality.

Database Design Process (review)
- Gather user needs / business
- Develop an ER Model based on user / business
- Convert E-R model to the set of relations (tables)
- To Normalized relations, to remove anomalies
- Implemented to create a database with a table for each relationship that have to normalized

Why normalization is needed?
- Optimizing table structures
- Increase speed
- The income data is the same
- More efficient in the use of storage media
- Reduce redundancy
- Avoid anomalies (insertion anomalies, deletion anomalies, update anomalies).
- Improved data integrity

A table saying good (efficient) or if the normal 3 to meet the following criteria:
1. If there is decomposition (decomposition) table, it must be guaranteed safe decomposition (Lossless-Join Decomposition). That is, after the table is described / in the decomposition into a new tables, the tables can generate a new table with the same exact.
2. Maintain dependence on the functional changes in data (Dependency preservation).
Does not violate Boyce-Code Normal Form (BCNF)
3. If the three criteria (BCNF) can not be met, then at least the table does not violate the Normal Form of the third stage (3rd Normal Form / 3NF).

Functional Dependency (FD)

Functional dependency (abbreviated FD) is a restriction that comes from the meaning of attributes and relationships between attributes.
Functional Dependency attributes describe the relationship in a relationship. An attribute said functionally dependant on the other, if we use the value attribute to determine the value of the other attributes.
Symbols used are to represent the functional dependency.

Notation : A -> B

A and B are attributes of a table. A means of determining the functional B or B depends on A, if and only if there are 2 rows of data with the same value of A, then B is also the same value

Notation : A ->/ B or A x-> B

It is the opposite of the previous notation

Example

Functional Dependency:

NRP -> Nama

Mata_Kuliah, NRP -> Nilai

Non Functional Dependency:

Mata_Kuliah -> NRP

NRP -> Nilai

Functional Dependency from the value table :

NRP -> Nama

Because for each value NRP the same, then the value of the same nama.

{Mata_Kuliah, NRP } -> Nilai

Because the value of attributes depending on the NRP and Mata_Kuliah together. In another sense Mata_Kuliah for the NRP and the same, they also rated the same, because Mata_Kuliah and the NRP is a key (is unique).

Mata_Kuliah ->/ NRP

NRP ->/ value

Normal Form

Normal form is a condition (using the FD and key) that determines whether a scheme relationships meet certain criteria. There are several normal forms based on a number of criteria:

Primary keys (1NF, 2NF, 3NF)
All Candidate Keys (2NF, 3NF, BCNF)
Multivalued dependencies (4NF)
Join dependencies (5NF)

First Normal Form (1NF)

A table on the form said to be normal if I did not reside in the unnormalized form of a table, where there is a kind of field multiplication and field that allows a null (empty) 1NF is not allowed on the:

Attribute values, many ( Multivalued attributes).
Attribute a composite or a combination of both.
Nested relations.

So, price is the domain attribute must be atomic rates.

Advantage of the 1NF compared Unnormalized relation (UNRs) is a simplification in the form of representation and ease of use in developing a query language

Second Normal Form (2NF) ~ 1
- Normal form 2NF met in a table if it meets the form of 1NF, and all the attributes than the primary key, have a full Functional Dependency on primary key
- A table does not meet 2NF, if there are attributes that it's Functional Dependency are only partial (only depending on the part of the primary key)
- If there are attributes that have no dependence on the primary key, then the attributes must be moved or removed

Second Normal Form (2NF) ~ 2
- Functional dependency X -> Y is full if it is said to delete an attribute A from X means that Y is no longer dependent functional.
- Functional dependency X -> Y said if deleting a partial attribute A from X means that Y is functionally dependent.
- Relation scheme R in the form 2NF if every non-primary key attribute A element R depend on the full functional primary key R.

EXAMPLE:

The following table meet 1NF, but not include 2NF

Does not meet 2NF, because (NIM, KodeMk) is regarded as the primary key:
(NIM, KodeMk) -> NamaMhs
(NIM, KodeMk) -> Address
(NIM, KodeMk) -> Matakuliah
(NIM, KodeMk) -> SKS
(NIM, KodeMk) -> NilaiHuruf
Table in the decomposition needs to be some of the table is eligible 2NF

their functional dependency as follows:
- {NIM, KodeMk} -> NilaiHuruf (fd1)
- NIM -> {NamaMhs, Address} (fd2)
- KodeMk -> {Matakuliah, SKS} (fd3)
So that:
- fd1 (NIM, KodeMk, NilaiHuruf) -> Value Table
- fd2 (NIM, NamaMhs, Address) -> Table Student
- fd3 (KodeMk, Matakuliah, SKS) -> Table MataKuliah

Third Normal Form (3NF) ~ 1

Normal form 3NF fulfilled if the form meets 2NF, and if there are no non-primary key attribute that has a dependence on non-primary key attributes of the other (transitive dependencies).

Table following students eligible 2NF, 3NF, but does not meet

Because the table above there are still non-primary key attribute (ie, Kota and Provinsi), which has a dependence on non-primary key attributes of the other (ie KodePos), namely:

KodePos à {Kota, Provinsi}

So that the table in the decomposition needs to be:

• Mahasiswa (NIM, NamaMhs, Jalan, KodePos)

– KodePos (KodePos, Provinsi, Kota)

Boyce-Codd Normal Form (BNCF)
Boyce-Codd Normal Form constraint has a stronger form of the Normal third. To be BNCF, relations must be in the form of First Normal form and forced each of the attributes depends on the function in the super key attributes.

Fourth Normal Form and Fifth Normal Form
- Relations in the fourth normal form (4NF) if the relation in BCNF and does not contain a lot of dependence values. To remove the dependency of many values from a relation, we divide the relationship into two new relations. Each relation contains two attributes that have a lot of relationship value.

5th Normal Form /5NF

Relations in fifth normal form (5NF) deal with the property called the join without any loss of information (lossless join). Fifth normal form also called the 5 NF PJNF (projection join normal form). The case is very rare and appear difficult to detect in practice.

References
1. Agus Sanjaya ER, S.Kom, M.Kom, slide presentation : Normalisasi
2. http://en.wikipedia.org/wiki/Database_normalization
3. http://kuliah.dinus.ac.id/ika/prc4.html
4. http://databases.about.com/od/specificproducts/a/normalization.htm

ER-Diagram

2009-04-18T20:07:00.000-07:00

Database definition

A group of on file data in disk magnetic, disk optical or is depository of other sekunder

Inwrought collection of datas which each other is interconnected the than an enterprise ( company, governmental institution or private sector)

· Manufacturing business = production planning data, data produce aktual, data ordering of material, etc

· Hospital = patient data, doctor, nurse, etc

DBMS

Group of database with software of application being based on database.

This application programs used to access and look after database.

Especial target of DBMS to provide an efficient and easy environment for the usage of, to withdrawal and is depository of information and data.

Bit, Byte, Field

Bit = representing part of containing smallest data of value 0 or 1.

Byte = corps of beets which of a kind.

Field = a group of byte-byte which of a kind, in data bases used by attribute term.

Field

Representing the nature of or characteristic from an entity providing to provide clarification of detail about entity.

An relationship also can have attribute.

Attribute example:

STUDENT: NIM, NAME OF, ADDRESS

CAR: NO_PLAT, COLOUR, TYPE, CC

Attribute type:

Multivalue Vs Single

Single = only can fill at most one value

Multivalue = can fill with interest from one value with same type

Composition Vs Atomic

Atomic = indiscrete into smaller attribute

Composition = representing aliance from some smaller attribute

Derived Attribute.

attribute which [is] its value can be yielded from other attribute value, for example = yielded age of attribute of[is date of delivering birth

Null Value Attribute

Attribute which [do] not have value to a[n record

Mandatory Value Attribute

Attribute which must have value

Record/ Tuple

Representing an data line in a[n relationship

Consist of attributes corps where attributes of interaction to inform entitas / relationship completely

Entity/File

File represent corps of record which of a kind and have [is] same element, [is] same attribute but different each other its data [of] him.

Type File

In application process:

File Mains

File Transaction

File Report

File History

File Protector

File Job/Activity

Domain

Domain represent corps of values enabled to stay in one or more attribute. Each;Every attribute in data bases of relasional defined by as a domain.

Data Element key

Key is element of record weared to find the the record when accessing or can is also used to identify each;every entity/record

Key type:

· Superkey represent one or more attribute from tables of able to be used to identify entityty / record of tables uniquely ( not all attribute can become superkey)

· Cadidate Key is super of key with minimum attribute. Key Candidate may not contain attribute of other tables so that key candidate beyond question superkey but not yet of course on the contrary.

· Primary Key

One of the attribute of key candidate can be selected / to be determined to become key primary with three criterion:

1. The Key more natural to be used as reference

2. The Key more simple

3. The Key well guaranted it

· Alternate Key is attribute of key candidate which is not chosen become key primary.

· Foreign Key represent any attribute subjecting to key primary at other tables. Key Foreign will happened at one particular relationship owning many to one kardinalitas ( one to many) or many to many ( many to many). Key Foreign usually always put down by tables of which is flange to many is.

· External [of] Key represent a[n attribute lexical ( or gathering of lexical attribute) which [is] its values always identify one object of instance.

ERD (Entity Relationship Diagram)

ERD is a network model using wording which is kept in system abstractionly.

Differencebetween] DFD and of ERD:

DFD represent an function network model to be executed by system

ERD represent data network model emphasizing at and structure of relationship data

ERD Elements

ENTITY

At ER Diagram of Entity depicted with square form of length. Entity is something that there is in real system and also abstraction where on file data or where there are data

Relationship

At ER Diagram of relationship can be depicted with a is lozenged. Relationship is natural relation that happened between entity. In general called with elementary verb. so that facilitate to conduct read of its relationship.

Relationship Degree

is the amount of entitas participating in one relationship. Degree of which often weared in ERD

Attribute

is the nature of or characteristic of each and also entitas of relationship

Cardinality

showing optimum of tupel able to berelasi with entitas at other entity.

Relationship Degree

Unary Relationship

is model of relationship that happened between entity coming from entity set is same.

Binary Relationship

is model of relationship that happened between 2 entity.

Ternary Relationship

representing relationship between instance from 3 type of entity unilaterally.

Cardinality

There are 3 relationship kardinalitas that is

To One One :

Storey;Level Relation one to one expressed with one occurence at first entity, only having one relation with one occurence at second entitas conversely.

To Many One or of Many One to :

Storey;Level Relation one to many is equal to many to one depended from which direction of relation that see. For one occurence at first entitas can have many relation with occurence at second entity, if on the contrary one occurence at second entity can only have relation with one occurence at first entity.

Many To Many :

happened if each;every occurence at a entity have many relation with occurence other entity.

Cardinality for example:

Notation ERD:

Symbolic notation in diagram of ER

1. Square of length express gathering of entity

2. Radian express attribute

3. Rhombic of relationship gathering

4. Line as link between relationship gathering with gathering of entitas Gathering and of Entitay with its attribute

DFD Quis

2009-04-05T00:04:00.000-07:00

”Data Flow Diagram”

data-flow diagram (DFD) is a graphical representation of the "flow" of data through an information system. It differs from the flowchart as it shows the data flow instead of the control flow of the program.

Data-flow diagrams (DFDs) are one of the three essential perspectives of the structured-systems analysis and design method SSADM. The sponsor of a project and the end users will need to be briefed and consulted throughout all stages of a system's evolution. With a data-flow diagram, users are able to visualize how the system will operate, what the system will accomplish, and how the system will be implemented. The old system's dataflow diagrams can be drawn up and compared with the new system's data-flow diagrams to draw comparisons to implement a more efficient system. Data-flow diagrams can be used to provide the end user with a physical idea of where the data they input ultimately has an effect upon the structure of the whole system from order to dispatch to report. How any system is developed can be determined through a data-flow diagram.

Is a diagram illustrating the system into smaller modules, which facilitate users with less understanding to understand the field of computer systems that will be done consists of a process and describe the scope of a system

context diagram

Diagram characteristics of context are:

· Consists of a process and describe the scope of a system,

· It is the highest level of the DFD that describes the entire system to input and output of the system,

· The system is limited by Boundary (depicted by broken line),

· No storage (storage).

Zero Diagram

Depicting process of DFD, Opening on to by totally about system handled, showing existing especial process or function, data stream and of external entity, At this level is enabled by the existence of data of storage, For process which is not detailed again at level hereinafter hence enhanced by symbol '*' or ' P' by the end of process number, Input balance and of output balancing between diagram 0 with context diagram have to be looked after

DIAGRAM DETAILED

Diagram Detailed to represent diagram elaborating process what there is in diagram zero or level above him.

In numbering of DFD, one level shall not there are more than 7 process and maximal 9, when more hence must be done decomposition.

SPECIFICATION OF PROCESS

Every process at DFD must to have the specification of process. At method level top used to depict process earn by using descriptive sentence. At more level detailed that is process most under ( primitive functional) requiring the specification of more structured. Specification of process will become guidance to programmer in making program ( coding). Method which is used in specification of process is the breakdown of process in the form of story, table decision, tree decision.

External Unity

External Unity is something that beyond system, but that give data into system or give data of system.

External Unity have symbol with notation box. External in this case entity, are not the including the part of system.

Naming:

· Name of terminal in the form of noun.

· Terminal may not have the same name, except its have same object its true.

DATA CURRENT

1. Representing place emit a stream of information [him/it].

2. Depicted with connective straight line of component of system.

3. Data current shown with direction bow and line called of data current emiting a stream of.

4. Data current emit a stream of among process, data of storage and show data current of data which in the form of input for system.

Guidance of giving name:

1. Name of data stream which consist of some word stream attributed to continued line.

2. There may not be any data stream which is same name and giving of name have to express its contents.

3. Data stream which consist of some element can be expressed with element grup.

4. Avoid usage of word ‘ data’ and ‘ information’ to give the name of data stream.

5. As possible the name of data stream written is complete

Another Rule:

1. Name of data stream which come into process may not same of name the output.

2. Data of Flow which step into or go out from data of storage needn't be called when:

· comprehended easy and simple Data stream

· Data stream depict entire/all data item

3. There may not be any data stream of terminal to data of storage or on the contrary because terminal non part of system, terminal relation with data of storage have to pass the process

Process

· Process represent what done by system.

· Process can process data stream or data enter to become exit data stream.

· Functioning process of transform one or some input data become one or some output data as according to specification of which [is] wanted.

· Every process have one or some input and also yield one or some output.

· Process often is also referred by bubble

Guidance of giving of the process name:

· Name of process consist of noun and vb. expressing process function

· Don'T use word process as part of the name of a[n bubble

· There may not be any some process owning the name of same

· Process have to give by number. Number sequence as possible follow process sequence or stream, but that way meaningless number sequence absolutely represent sequence process chronologically

Data Storage represent existing data repository in system.

1. Symbol with a couple of parallel line or two line wrongly one side from other side openly.

2. Process can take data from or give data to database.

3. Guidance giving of name:

· Named have to express data of storage.

· If its name more than one word hence have to say the word to joint.

Data dictionary

· Function to assist perpetrator of system to interpret application in detail and organizational all used by data element system precisely so that user and system analyst have same congeniality base about input, output, depository and process.

· At analysis phase, data dictionary used as by communication means between system analyst with user.

· At phase scheme of system, data dictionary used to design input, database and report

· Data current at DAD have the character of globally, boldness more detailed can be seen by data dictionary

Data dictionary load the followings:

· Name of data current: have to be noted reader to needing furthermore clarification about a data current can look for it easily.

· Alias: name or alias of[is differ from data can be written by if there are any.

· Data form: used to group data dictionary into its use time scheme of system.

· Data current: showing where from data emit a stream of and where data go to.

· Clarification: giving clarification about meaning of data current.

Balancing at DFD

1. Data stream which come into and go out from one process have to equal to data stream which come into and go out from detail of process at level / level below/under it.

2. Name of data stream which come into and go out from one process have to equal to name of data stream which enter into and go out from detail of process

3. Amount and name of entity external from a process have to equal to name and amount of entity external from detail of process

4. Things which must be gave attention to DFD owning more than one level:

· Have to there are input balance and of output [among/between] one and level of level next

· Balance between level 0 and level 1 seen at input / output of data stream to or from terminal at level 0, while balance between level 1 and level 2 seen at input / output of data stream to / from pertinent process.

· Name of data stream, data of storage terminal and every level have to be same if its have same object.

Prohibition order in DFD

1. Data current may not from direct external entity go to other external entity without passing the process.

2. Data current may not from direct data deposit go to external entity without passing the process.

3. Data current may not from direct data deposit go to other data deposit without passing the process

4. Data current from one direct process go to other process without passing the data deposit , it can possible to avoided.

Reference:

ER Ngurah Agus Sanjaya. Slide Part 4 - DATA FLOW DIAGRAM.

Wikipedia. Link: Data_flow_diagram.htm

Parno, SKom., MMSI. Data Flow Diagram

Fourth Quis

2009-03-28T20:57:00.000-07:00

INITIAL OBSERVATION AND REQUIREMENT ANALYSIS

System investigation concept

Differential between system purpose and real condition of system

Gap between system purpose and real condition of system, that usually causes by the failure of the system, and how to understanding why other systems failed to achieve the goals that the system has been determined previously. The analyst must know the different and the mistakes of the system to solved the problem. With the investigation that we know what must we do if there are something problem about differential between system purpose and real condition of the system.

Reports in the detection problem may not actually be real or can not be solved. This may be because:

v The purpose to ideal, can make difficult to realize the system destination and the report of system investigation will be failed.

v The system can not be developed because of lack of resources, attitudes, or both.

v Measure the system not accurate. The lack of measuring system can make an error report of investigation system.

v Statement of goals is dated.

v Different between idle system and temporary system. It can make the system be difficult cause have a crucial differential.

Problem solving:

Accurate investigation
Get a ideal consensus system
Expand some alternative
Choose the best alternative

~~Investigation Purpose to indicate the real problem

Constraint in Investigation System

When doing investigation, we have some problems:

1. Time

System investigation need a lot of times, so we must use it very well to balancing the efficiency.

2. Cost

Often the costs incurred related to the length of time for activities investigas, so that management will give the limits of cost.

3. Knowledge

Lack of project knowledge will impact on the results of investigations that are less mature or complete.

4. Politic

Management or the parties may distribute certain issues which aim to restrict the investigation activities.

5. Interference

Control activities in investigate that will disrupted. The investigation will failed like that.

Recommendation

Result of investigation is a recommendation which is filled with:

- Never take any action

This is mean when there is no problems find in system we can’t take any actions.

- System maintenance

System maintenance needs to maintenance small problems like when job description not runs very well. So we must solve that problem and after we solve it we must maintenance.

- increase ability or user ability

- Totally consider to system modification

- Put problem into the development system plan

Investigation tactic

Why need some tactic?

1. To find all the problem.

We must find all about our problem

2. To find out the reason.

We must find a reason of our problem.

3. To find out the best solution.

We must find the solution to solve our problem

Investigation tactics need to all element system be able to receive offer solution without interrupt their activities.

Several tactics:

listen suggestion from system agent
don’t give first solution
consideration several stories from system agent about same cases
notice the logical inconsistent problem

Investigation Technique

Direct:

Ø Questioner

Ø Question and Answer

Ø Monitoring

Non-direct:

Ø Current procedure

Ø Learn the document

Ø Sample

Ø Tabular

System description at this time

Determine the performance of the system at this time will have difficulty when
company does not have a standard performance measurement system.
Unfortunately, companies tend not to update
documentation systems that are running. Therefore, analysts improve document system problems during the investigation.
Description of the system include a clear explanation at this time:
a. Inputs
b. Outputs
c. Files
d. Data elements
e. Transaction volume document and action
f. Data flow diagrams

Analysis Requirement

Intensive interaction stage between systems analyze with end user when team development system show their skill to get some reaction and trust the user until the get good participation.

4 goal wish to achieve:

v Explain the system completely

v Describe the ideal information system

v Bring the ideal information system at moment with observe the resource constraint

v Give push to user conviction into development system

Method:

v Interviews

v Questioner

v Observation

v Current procedure

v Document monitoring

Resource constraint

v Time

v Cash

v Skill

v Technology

v External factor

Document analysis requirement

v Analysis direction: relationship with the end user, process monitoring, problems in data gathering.

v User needs: real needs, report needs, exercise needs, and new system influence.

v System constraint: explain time and cost constraint, skill, technology and external factor.

v Document kind data gathering instrument, statistic consensus, data flow according to physic and logical, first data element in data dictionary.

Generating Systems Alternatives

How do approach the condition of the system at this time with the condition of the ideal system?

We can create alternative care to solve the information system.

The best alternative can applied wisely.

Strategy selection

v Distributed versus centralized processing.

Change information decision from centralized data processing to decentralized end user responsibility center.

v Integrated versus dispersed database.

System planner must consider what kind of incoming data to database and incoming to file.

v Surround Strategy of System Development.

Environs are important strategy in case overtake company because information system from other company possible different with company at moment.

Selection tactic

Do before operational planner selection started. If we can make some tactic before doing operational planner, we can choose the best tactic to solve the problem.

Operational planner selection

Operational planner selection

Planner selection is able categorize into:

Ø Input

v Online Vs Off Line Data Entry

v Keyed Vs Machine Readable Data Entry

v Centralized Vs Decentralized Data Entry

Ø Processing

v Batch Vs Real-time record update

v Sequential Vs Direct Access to records

v Single Vs Multiple User update of records

Ø Output

v Traditional Vs Turn Around Documents

v Structured Vs Inquiry based reports

Selecting the Proper System

Equal tactic is equivalent system based on cost and profit relatively. There is three system, A is more excellent with other system if:

A have low cost then B and their profit same.
A have low cost then B and A produce profit more than B.
A and B have same cost but produce of profit A more than B.

Several comparative method system

Break Even point analysis
Payback period
Discounted payback period
Internal rate of return

Cost category

Hardware
Software
People
Suppliers
Telecommunications
Physical sites

Cost details

Equal system information cost by means of life system, analyst projection several cost change for future and 3 cost model information system that is Linear, Exponential and Step Function.

Information system cost happen in one time and be able happen continuous.

Information system cost happening in one time that is on-time cost and development cost while system development consist.
Information system cost happening continuous there are recurring cost with operational cost while cost happen at information system operated every day.

Information System Factor

Qualitative factor direct to best information system there are:

reduce mistake state
reduce time to solve mistake
reduce perceptive time from alternative workstation
increase time to supplying information
raise system security
increase update from active record
raise user satisfied

Company Strategy Factor

- user satisfied

- increase selling state

- commitment between consumer and vendor

- product information marketing

Representation Learning System

shortly presentation
reduce technically details
represented clearly with visual tools
if use model, use tools like laptop so more informative
pushed profit from information system proposal with several alternative agree with company condition

Advanced Decision or Not

If company decision to develop the system then information department will doing advanced process there is system design process
If the other way then System Development Life Cycle (SDLC) will stopped.
Often find problem with studying system and usually top management will asked to do re-processing with studying system.
Model will explained several continuous state and sometime information department will create decision to repeat state before explain studying system.
With alternative, decision to repeat a state System Development Life Cycle (SDLC) before or not called Go – No –Go Decision

GENERAL OBSERVATION FOR SYSTEMS DEVELOPMENT

2009-03-07T20:31:00.000-08:00

The necessary of systems development

1. Problems

Problem in the systems is mistakable of the systems, that make the old system not work optimally. There are some mistakes:

- The miss understanding of system between programmer and user.

- The operations is not correct make the system error.

- Didn’t obey the management rule, so the system will not optimally

- etc

2. The growth of organization is not effectives

The old system is not optimal to fulfill the requirements of organization, so the organization needed new system to complete the job optimally.

3. Get the opportunities

Systems development is needed to get opportunities, for example: the organization want to renew their systems to raising quality and also to upgrade their income.

4. Directives

Systems development is needed, because there are some instruction from the leader, or the rule from the government.

The aim of system development

1. To solve the problems

2. To get the opportunities

3. To fulfill the instructions

For the general the aim has been written on top.

What can we hopes from the new system?

Ø Performance

The new systems can raising the performance of organization. If the performance is low, the new system will be able correcting then upgrade their performance better than the old system.

Ø Information

There are raising about the quality of information, so information that needed always new and fresh because the function of new systems.

Ø Economy

New system will upgrade the benefits or to go down the account.

Ø Control

New systems will control and also fix any problems in organization.

Ø Efficiency

The improvement of operating efficiency. Efficiency related with how to use resource without doing extravagance

Hopes new system can control efficiency jobs:

Outcome

income

Ø Services

New system will raising the services. If old system have bad services, we hope with the new system will give better.

Principle systems development

- Systems for management always developed for raise the information of management system.

- System for big invest.

The system need big invest besides if we use modern technology, so the organization must consider two alternative:

o To go down the opportunities cost has will gone

o To consider by analyst that benefits cost to detect about that invest project can be benefit or no.

- System need specialist in their sector and not always need people who get formal education

- Job levels

The job levels in system development use system development life cycle

- System development not must be processed from first until next procedures, but also can process with random or customs.

SYSTEM DEVELOPMENT LIFE CYCLE

The Systems Development Life Cycle (SDLC) is a abstract model used in project management that describe the stages concerned in the information system development project from an initial probability study through maintenance of the completed application. Various SDLC methodologies have been developed to guide the processes concerned including the waterfall model (the original SDLC method), rapid application development (RAD), joint application development (JAD), the fountain model and the spiral model. Generally, several models are united into some sort of hybrid methodology. Documentation is critical in spite of the type of model chosen or devised for any application, and usually done in parallel with the development process. Some methods work better for definite types of projects, but in the final analysis, the most important factor for the success may be how directly particular plan was followed.

Waterfall method:

In this cycle, the process always start followed the procedures. The process start from bring together about requirements and analyst all of data to the next process. If the requirements have done, we go to next process is called design of the system. We can design the system use all of data from the requirements. And then the design of the system can we implementation with evaluated and also we can do testing to use this system.

Next procedures is how can we verification this system to be good system, and we introduce to many user that will use this system.

If all of procedures on top have done, the system must we protect from the bad sectors using maintenance.

Iterative method

Iterative cycle have the same instruction with the waterfall cycle. The different we found in the maintenance procedures. The system have testing level and evaluation level in this procedures. If we found any mistakes can we bring together be new requirements and go to next level like the picture on top. The levels in iterative cycle which is connected each other.

Spiral method:

This model of development combines the features of the prototyping model and the waterfall model. The spiral model is favored for large, expensive, and complicated project.

Spiral model have many procedures to do:

The new system requirements are definite in as much detail as possible. A prelude design is formed for the new system. At first prototype of the new system is constructed from the preliminary design. The 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. The existing prototype is evaluated in the same manner as was the preceding prototype, and, if necessary, another prototype is developed from it according to the fourfold procedure outlined above. The preceding steps are iterated until the customer is satisfied that the refined prototype represents the final product desired. And also the final system is constructed, based on the refined prototype then evaluated and tested. Routine maintenance is carried out on a continuing basis to prevent large-scale failures and to minimize downtime.

Approaches of developing a system

Classic approach vs. approach of structure

Classic approach methodologies develop system by following steps in system of life cycle. One who develop this system still need techniques and appliances to develop the system. Problemss of arising out in classic approach shall be as follows:

1. Development of software will become difficultly

2. Expense of treatment or conservancy of system will become costlierly

3. Possibility of mistake of big system

4. Efficacy of system less well guaranted

5. Internal issue applying of system.

Approach of structure

Still use tools-tools like data of flow diagram. Approach of structure basically try to provide to additional system analyst of techniques and appliances to develop system beside remain to follow idea of system of life cycle. Conception system development of structure not such a new concept. Assembling technique in factories and scheme of circuit for the appliances of electronic are two example of this concept which used many industrys.

Piecemeal approach vs. system approach

Piecemeal approach is system approach development that emphasized at one particular activity or certain application. This approach don’t heed overall target. System approach pays information system as integration unitary to each activity or the application. This approach also emphasized in overall goal achievement from organization, not only in that information target.

Approach of bottom-up vs. approach of up-down

Bottom-Up Approach had begun from level under organization, that is begun from needs formulation to handle transaction and climb level on with formulate information need based on transaction. This approach also is feature classic approaches. Bottom-up approach is used in systems analysis stage is called also with data analysis, because that be pressure data that be cultivated before hand, information that be produced to follow to follow the data. this approach strarting from under level organization, that is operational level where transaction has done.

Top-Down Approach on the contrary begun from level on organization, that is begun with define target and organization policy. Step furthermore from this approach information need analysis. After information is determined, so process goes to transaction processing, that is determination output, input, data base, operating procedure and control. This approach be feature from structured approach. Top-down approach when used in systems analysis stage called also with term decision analysis, because that be pressure information that wanted for decision making by management beforehand, then data necessary cultivated to defined to follow information that wanted.

Comprehensive system vs. modular approach

approach by totally represent approach developing system in concern by totally. this is approach less synchronized for the system of big money, because will become difficult to be developed. this approach also represent marking of classic approach

Total-system approach to be approach develops system together according to comprehensive. This approach less synchronized for complex system.

Modular Approach tries to divide complex system to simple some part, so that system easier will be understood and developed. Furthermore consequence system can be developed of time that planned, easy understood by system user and easy to maintain. This approach be feature structured approaches.

great-loop approach vs. evolutionary approach

Great-loop approach applies change comprehensive according to together use sophisticated technology. This change contains many risks, because computer technology so great-loop. This approach also too expensive, because need investment at the same moment for all technology that used and difficult to developed because too complex. Evolutionary approach apply sophisticated technology just for applications that need that moment and then be developed for periods next based on technology development. This approach causes investment not too expensive and can follow fast technology development.

system development methodologies

The meaning of methodology, method and algorithm ????

Methodology is unity of methods, procedures, jobs concepts, the rule of postulates and used by an science, artistic or the other discipline. Method those are utilized in scholarship.

Method is someway systematic to work something

Algorithm is medley procedural to solves a problems

The classifications of development methodology

There are three classifications of developing a system, such as:

Functional decomposition

Functional decomposition is emphasizing system resolving becomes subsystem. Examples of this classification are HIPO, Stepwise refinement, iterative stepwise refinement and information hiding.

Data-oriented

Data-oriented is emphasizing on processed data characteristic.

Flow oriented data: types appropriate modules data elements
Structure oriented data: input structure and output
Prescriptive methodology

which the included in this methodologies:

- ISDOS (information system design and optimization system)

- PLEXSYS

The function is to transform statement fro computer language into executable code to configure hardware that we need.

- PRIDE

Software to analyst and design some structure system for development system.

- SDM/70(system development methodology/70)

- SPECTRUM

- SRES AND SREM

- Other prescriptive methodologies

Usually been provided by software maker factory

Tools for developing a system

Get graph form: HIPO, SADT, Jackson’s diagrams, etc.
Tool that utilizes to design:

Activity charting: figuring activity, example: chart’s substituting, flowchart, etc.

Layout charting: figuring layout

Personal relationship charting: figuring person relationship, example: organization chart, working distribution chart

Techniques used in developing a system

Project management techniques à to scheduling project, example: CPM and PERT
Tech finds fact à to gather and determines data / fact

*> Interview

*> Observation

analysis’s tech cost / benefit à cost benefit and cost effectiveness analysis
Going tech shuts close
Inspection tech

The differences of being a system analyst and a programmer and the knowledge a system analyst should posses

System analyst studying problems and determine system user requirements to identify resolving.

Programmer writing program code bases engineering that made by analyst

Ø System analyst on call bridges distinctive happening science among system user and Data processing technology, computer and mathematics

Ø Science carries on business in common

Ø Quantitative method: regression, programming linear, etc. it

Ø Trouble-shooting membership

Ø Communication membership among person

Ø Membership builds relationship among person programmer

Analyst and Design of Information System

2009-02-20T19:23:00.000-08:00

Basic of System Concept

Definition system can be looked from two research there are procedures research and component research.

System is a network of procedures which is connected each other, grouping together to do some work to reach an aims.

Research to the system there are network from procedures that explain the accounts on the system. Procedures are an account as clerical operation which is involved by some people in one or more department, which is use to guarantee the balance of handling the business transactions.

Procedures are correctly chronologies from levels of instructions which is explain what we must doing, who will do it, when it will be doing, how to do it.

Research to the system more explain for element or component that gives definition of the system as group from the elements which interactive to get the goal.

Learning a system will be better if we know the meaning of the system at first. Components or subsystems in a system cannot stand by them self/alone. Components or subsystems relates each other to make a union to reach the goal of the system.

Characteristic of System

The system has a specific characteristic there are components, boundary, environments, interface, input, output, process, and objectives or goal.

1. Component

System made from components which interacted each other and build one union. Every system always have components or subsystem. A system can be heve a bigger system, named Supra system. If industries as a system, then department be subsystem, and also if department be a system so accounting system be the subsystem. If accounting system we looked as be a system then department are the supra system and industries are supra from the supra system.

2. Boundary

Boundary have a place which lines between systems, or between systems with the environment lines of the system showed the scope of it.

3. Environment

Is everything that placed outside of the lines of the system.

4. Interface

Interface is a media to connect the subsystem between one to another.

5. Input System

Input is the power which is added into the system. There are two type of input:

1. Maintenance input

2. Signal input

6. Output System

Output is a goal from the process power and classified into good output.

7. Process

The process will be change the input become output.

8. Objectives

A system must be have goal or objective. If there are have no goals, it will be useless. The system which is can reach the goals can be called successful.

Classification system

A system can be classified from some point of view, there are:

1. System can be classified into abstract system and physical system. An abstract system is a system that we cannot see it. Example: the idea

Physical system is a system that can be looked, Example: computer system, account, production, etc.

2. System can be classified into natural system and human made system.

3. System can be classified into deterministic system and probabilistic system.

4. System can be classified into closed system and open system.

Basic of Information Concept

Information is a data which is processing into meaningful form that are more whortless to the receiver.

Information Cycle

Data is a rare form which is cannot tell a lot of thing. So it need to process to meke an information.

Quality of Information

Quality of information depend on the accurate, timelines, and relevance.

Accurate = information must free from the error

Timelines =information come to the receiver cannot late

Relevance =information must have benefit for user

Valve of Information

Valve of information come from two things, there are function and account. Some information have valve if their benefit more effective compared with their account. A lot of information that cannot be reach by valve of money, but it can be reach by valve of effectiveness.