DATABASE AND ER-Diagram

DATABASE DEFINITIONS

The database is a set of data stored in the magnetic disk, optical disk or other secondary storage. Besides, the data base can also be defined as the collection of data, which can be described as the activities of one or more organizations that be relations. The database can be a collection of integrated data-related data of an enterprise (company, government or private). For example:

1. Company data à manufacturing production planning, actual production data, data, material ordering, and so forth.
2. à hospital patient data, doctor, nurse, and so forth.

DBMS (Database Management System)

DBMS is a collection of databases or a combination of software-based database applications. DBMS is a software designed to assist in the maintenance and utility data collection in large numbers. Application programs are used to access and maintain databases. The main purpose DBMS is to provide an environment that is efficient and easy to use, withdrawal and storage of data and information.

BIT, BYTE, Field

1. Data bit is the part that contains the smallest value of 0 or 1
2. Bytes-bit set of bit similar
3. Field set of byte-byte similar, in the database used the term attribute

ATTRIBUTE OR FIELD
Attribute is the nature or characteristics of an entity that provides provide detail on these entities. A relationship can also have attributes. Example attributes:

1. STUDENTS: NIM, NAME, ADDRESS
2. CAR: NOMOR_PLAT, COLOR, TYPE, CC

ATTRIBUTE TYPES

• Single attribute vs multivalue attribute

Single attribute is an attribute that can only be filled at most one value.
Multivalue attribute is an attribute that can be filled with more than one value with the same type.

• Atomic vs composition

Atomic attribute is an attribute that can not be divided into smaller attributes.
Composite attribute is a combination of several attributes of a smaller.

• Derived attribute is an attribute whose value can be derived from the value of other attributes, such as age that resulted from birth date attribute.
• Null Value attribute is an attribute that has no value to a record.
• Value attribute is a mandatory attribute that must have a value.

RECORD / TUPLE
Record is a data line in a relationship. Record consists of a set of attributes where the attribute is an attribute-related entity or to inform the full relationship.

ENTITY / FILE
Entity is the object or objects in a certain mini world represented in the database. Entity can be:

1. Things that have physical (people, cars, houses, etc.)
2. think that there are conceptual (enterprise, employment, discipline, etc.)

File is a collection of similar records and have the same elements, the same attributes but different data values. In processing applications, files can categories with several types as follows:

- Master File
- Transaction Files
- File Reports
- File History
- File Protection
- File Work

DOMAIN
Domain is the set of values that are allowed to reside in one or more attributes. Each attribute in a database relational is defined as a domain

KEY DATA ELEMENT
Key elements of record which is used to find these records at the time of access, or can also be used to identify each entity / record / line.

SPECIES OF KEY
There are several types of key in the ERD, namely:

• Superkey is one or more attributes of a table that can be used to identify entityty / record of the table are unique (not all attributes can be superkey)
• Cadidate Key is a super key with minimal attributes. Candidate must not contain a key attribute of the table so that the other candidate key is certain superkey but not necessarily vice versa.
• Primary Key One of the key attributes of the candidate can be selected / specified a primary key with the three criteria, namely:

1. Key is more natural to use as reference
2. Key is more simple
3. Key is guaranteed unique

• Alternate Key is the attribute of the candidate key is not selected to be primary key.
• Foreign Key is any attribute that points to the primary key in another table. Foreign key will be going on a relationship that has cardinality one to many or many to many. Foreign key is usually always put on the table that point to many.

• External Key is a lexical attribute (or set of lexical attributes) that values are always identify an object instance.

ERD (Entity Relationship Diagram)
ERD is a model of a network that uses word order is stored in the abstract system.
Differences between the DFD and ERD, namely:

1. DFD is a model of network functions that will be implemented by the system.
2. ERD is a model that emphasizes the network data on the structure and relationship data.

Elements of the ERD

• Entity

In the ER Diagram, Entity is described with the rectangular shape. Entity is something that exists in the real system and the abstract where the data stored or where there are data.

• Relationship

In the ER diagram, relationship can be described with a lozenge. Relationship is a natural relationship that occurs between entities. In general, the name given to the verb base making it easier to do the reading it relations.

• Relationship Degree

Relationship Degree is the number of entities participating in a relationship. Degree which is often used in the ERD.

• Attribute

Attribute is the nature or characteristics of each entity and relationship.

• Cardinality

Cardinality show tuple maximum amount that can be relations with entities on the other entity.

Relationship Degree
There are several types of degree of relationship, namely:

• Unary Relationship

Unary Relationship model is the relationship between the entity originating from the same entity set.

• Binary Relationship

Binary Relationship model is a relationship between 2 entities.

• Ternary Relationship

Ternary Relationship is a relationship between the instance of 3 types of entities are unilateral.

CARDINALITY
There are 3 cardinality relations, namely

• One to One: Level one to one relationship with the one stated in the entity's first event, only had one relationship with one incident in which the two entities and vice versa.
• One to Many or Many to One: Level one to many relationship is the same as the one to many depending on the direction from which the relationship view. For an incident on the first entity can have any relationship with many incident on the second entity, if the one incident on the second entity can only have one relation with the incident on the first entity.
• Many To Many: if any incident occurs in many entity have relationships with other entities in the incident.

EXEMPLARY CARDINALITY

Notation (E-R diagram)

Symbolic notation in the ER diagram, namely:

1. Rectangle represent the collective entity
2. Circle represent the attributes
3. Rhomb represent collective relationships
4. Line as the set of relationships between the entity and the collective entity with the attribute

Reference:

1. ER Ngurah Agus Sanjaya. Slide Part 5 - DATABASE DAN ER-DIAGRAM.
2. Elmasri & Navathe, Fundamental of Database Systems, 5th Edition, Chapter 3, 2007. ¨

DATA FLOW DIAGRAM

DATA FLOW DIAGRAM

Data flow diagram also called Data Flow Diagram (DFD). DFD is to describe the system modules in a smaller and less easy for the user to understand to understand the field of computer systems that will be done.

DFD also serves to describe the existing system or the new system will be developed logically without considering the physical environment where the data flows, or where data are stored. DFD is a tool that is used in the system development methodology is structured (structured analysis and design). DFD can describe the flow of data within the system with a structured and clear.

CONTEXT DIAGRAM

Context diagram of a process and describe the scope of a system and is the highest level of the DFD that describes the entire input to the system and output of the system. System in the context diagram is limited by Boundary (depicted by broken line). In the context diagram can not have storage (storage).

ZERO DIAGRAM

Zero diagram is a diagram describing the process of the DFD. This diagram provides a view of the overall system in which, showing the main function or process that is, the flow of data and external entity. At this level of data storage possible.

For the process that is not explained in the next level then added to the symbol '*' or 'P' at the end of the process. Balance of input and output (balancing) between 0 to diagram context diagram should be maintained.

DETAILED DIAGRAM

Diagram is a detailed diagram of the process of decipher what is in the diagram zero level or above.

Rules on numbering level DFD:

In one level there should be no more than 7 units and the maximum of 9, when more should be done in the decomposition.

SPECIFICATION PROCESS

Each process in the DFD must have a specification process. At the top level method is used to describe the process you can use with descriptive sentences. At a more detailed level, namely on the bottom (functional primitive) require a more structured specification.

EXTERNAL ENTITY

Specification process will be the guideline for the programmer to make this program (coding). Method used in the specification process: the process of disintegration in the form of a story, decision table, decision tree.

Unit outside is something that is outside the system, but it provides data in the system or to provide data from the system. A symbol of unity in outside the box with the notation. External entity does not include part of the system.

Rules for naming:

1. The name of the noun form.

2. Terminal may not have the same name except the same object (described twice, is intended to more clearly make the diagram). If so, then the terminal should be a forward slash in the top left corner.

3. Name of the flow of data into a process may not be the same as the name of the data flow out of the process.

4. Data flow into or out of the data store does not need to be given a name if:

• Flow data is simple and easily understood.

• Describes the data flow of all data items (one record intact).

5. There can be no flow of data from the terminal to store data or on the contrary, because the terminal is not part of the system. Relationship with the terminal must store data through the process.

External entity symbols:

DATA FLOW

Data flow is place where the information flow. Depicted with the straight line that connects the components of the system. Data flow direction indicated by arrows and the given name on the flow of data flow.

Data flow, flow between processes, data storage and data flow indicates that the form of data input to the system.

Guidelines of the name:

1. Name of the flow of data that consists of some words associated with the flow line speed.

2. No flow data for the same and the name should reflect its contents.

3. The flow of data that consists of several elements can be expressed with the group elements.

4. Avoid using the word 'data' and 'information' to give a name to the flow of data.

5. Wherever possible the complete flow of data is written.

Other provisions:

1. Name of the flow of data into a process may not be the same as the name of the data flow out of the process.

2. Data flow into or out of data storage does not need to be given a name if:

• Flow data is simple and easily understood.

• Describes the data flow of all data items (one record intact).

3. There can be no flow of data from the terminal to the data storage, or vice versa because the terminal is not part of the system, the relationship with the terminal data storage must be through the process.

Data flow symbols:

There are some concepts of data flow that must be considered, namely:

1. The concept of packet data (packet of data).

When two or more data flows from a source to the same destination the same, so should be considered as a single data flow.

2. The concept of data flow spread (diverging data flow).

Shows a number of copies of the same data flow from the same source to a different destination.

3. Gather the data flow concept.

Shows some of the different data flows from different sources join together towards the same goal.

4. The concept of destination and source of flow data.

All data flows must be generated from a process or to a process (can be one or both, that is derived from a process leading to a process is not derived from or is not a process leading to a process or a process come from and go to a process).

PROCESS

The process is also often called bubble is what is done by the system. The process can process the data or incoming data flows into outgoing data flow. Transform the process of working one or more of the input data into one or more of the output data in accordance with the desired specifications. Each process has one or more inputs and produce one or several outputs.

Guidelines of the process:

1. Name of the process consists of a verb and noun, which reflects the function of the process.

2. Do not use the process as part of the name of a bubble.

3. May not have some process that has the same name.

4. The process should be given a number. Order number wherever possible to follow the flow of the process or sequence, but the sequence number does not mean that the absolute is a process in chronological order.

5. Numbering process on the first level (the diagram is zero) is 1.0, 2.0, 3.0, etc.

6. Numbering process on the second level of 1.0 (the details of the process 1.0) is 1.1, 1.2, 1.3, etc.

7. Context diagram (context diagram) does not need to be given a number.

8. The process is the lowest 2.x, not explain again.

Process symbols:

DATA STORAGE

Data storage is a storage place for data that exists in the system. In a symbol with a pair of parallel lines or two lines with one of the side open. The process can retrieve data from or provide data to the database.

Form of data storage are as follows:

• A file or database in the computer system.

• An archive, or manual entry.

• One box of data in a table.

• A table reference manual.

• A book or agenda.

Guidelines of the name:

1. The name should reflect the data storage.

2. When his name more than one word must be marked with the number.

Data storage symbols:

DFD SYMBOLS



DATA DICTIONARY

Data dictionary is also called with a system data dictionary is a catalog of facts and data information needs of an information system. Working data dictionary to help the system to interpret the application in detail and organize all elements of the data used in the system precisely so that the system analyst and have a basic understanding of the same input, output, storage and processing.

In the analysis phase, the data dictionary is used as a means of communication between the systems analyst with the user. While in the system design phase, the data dictionary is used to design input, reports and databases.

Flow data on the global DAD, further details can be seen in the data dictionary. Load the data dictionary as follows:

1. Name of data flow: must note that readers who need further explanation about a flow of data can find it easily.

2. Alias: alias or other name of the data can be written if there is.

3. Forms of data: used to segment the data dictionary to use when designing the system.

4. Flow data: indicates from which data flows and where the data.

5. Description: to give an explanation of the meaning of the data flow.

BALANCING IN DFD

There are some balancing between input and output in the DFD, such as:

1. The flow of data into and out of a process must be the same as the flow of data into and out of the details of the process on the level / levels below it.

2. Name of the data flow into and out of the process must match the name of the flow of data into and out of the details of the process.

3. Number and the name of an entity outside the process must be equal to the number of names and entities outside of the details of the process.

4. The issues that must be considered in the DFD which have more than one level:

• There must be a balance between input and output of one level and the next level.
• Balance between level 0 and level 1 at the input / output of stream data to or from the terminal on level 0, while the balance between level 1 and level 2 is seen on the input / output of stream data to / from the process concerned.
• Name of the flow of data, data storage and terminals at each level must be the same if the object is same.

RESTRICTIONS IN DFD

To drawing DFD, there are a few rules or restrictions that must be so in its drawing is not an error occurs, these rules are:

1. Flow data may not be from outside the entity directly to other outside entities without going through a process.

2. Flow data may not be from the savings directly to the data to outside entities without going through a process.

3. Flow data may not be saving the data directly from the savings and other data without going through a process.

4. Flow data from one process directly to the other without going through the process of saving data should or be avoided as much as possible.

DIAGRAM CASH INVESTMENT DATA

There are 2 forms of the DAD:

a. Physical Data Flow Diagram (DADF), more appropriately used to describe the existing system (old system). The emphasis is how the processes of the system is applied (in a way what, where and by whom), including manual processes.

b. Data Flow Diagram Logic (DADL), more appropriately used to describe the system that will be proposed (new system), with no emphasis on how the system implemented, but the emphasis only on the logic of the demand system, that is what the process logic needed by the system.

GUIDELINES TO DRAWING DFD

How to draw the following guidelines for good DAD, DADF or DADL. Example below is for DADL but can also be used for the DADF.

1. Identify the first unit outside of all involved in the system.

For example, sales for the system have involved foreign entity such as customer, credit manager, the warehouse and the delivery.

2. Identification of all input and output involved in union with the outside.

3. First image context diagram (context diagram). DAD is a tool for structured analysis. The structure of this system to try to describe the first time the outline (top level) and split them into the more detailed (lower level) is called overview diagram (level 0). Each overview will be drawn more detailed again called level 1, and each process in level 1 will be drawn back with a detailed level with a 2 and so on until each of these processes can not be drawn again.

4. Chart image tiered process for all that is in the system first. Tiered chart (hierarchy chart) used to prepare DAD drawing to more levels down again. Tiered chart can be drawn using the notation in the DAD.

5. Image to sketch DAD overview diagram (level 0) process based on the tiered chart.

6. DAD-level image to the next level-1 level and beyond.

For example, application DAD sales transactions that must be drawn is a level 1 to process 1, process 2 and process 3.

7. After all drawn level DAD, DAD is drawing to a management reporting drawn separately.

8. After all drawing is wrong, then all this DAD combined in one diagram.

Reference:

1. ER Ngurah Agus Sanjaya. Slide Part 4 - DATA FLOW DIAGRAM.
2. HM, Jogiyanto. 2007. Analisis & Desain Sistem Informasi. Yogyakarta: ANDI.

BEGINNING OBSERVATION, ANALYSIS REQUIREMENT

INVESTIGATION SYSTEM CONCEPT

System investigation here is done when there is or there is a gap in the difference (gap) between the purpose of the system and actual system conditions. For example, the system is to satisfy customers in terms of services company, but the system has a condition which can not satisfy customers, as early goals of the system is made, so that here the system is needed to improve the system of investigation that has been there.

There is a system of investigation here also be due to a detection of the problems that the report does not really real, such as:

• Too ideal destination
• Lack of resources and / or attitude
• Measurement system is less accurate
• System that is the purpose behind
• The difference between the ideal system and the system while

Problem solving:

• Decompose the system is running.
• Where is the investigation carried out here in detail
• Getting a consensus that the ideal system
• Developed several alternative
• Selecting the best alternative

The objective of the investigation here is to show that the problem actually occurs.

CONSTRAINTS SYSTEM INVESTIGATION

In making an investigation, there are several problems that often arises, namely:

• Time
• Cost
• Science
• Politics
• Intervention

RECOMMENDATION

Results of the investigation is a recommendation that includes among others the following:

• Not to take any action.

This is done because there is no problem in finding a system.

• Perform system maintenance.

Here because of the maintenance problems that caused a small system that does not run in accordance with the goals, so that we do live on the repair and maintenance of the system.

• Improving the ability or the skills
• Consider modifications to the system total
• Putting the problem to occur in the development plan system is carried out immediately

INVESTIGATIONS TACTICS

Investigation tactics is needed here so that we:

• Find all issues
• Knowing the causes of the emergence of problems
• Determine the appropriate solution

Besides, the tactics that the investigation carried out all elements of the system can receive a quote a solution without disrupting their activities

Some of the tactics that can be done:

• Listen to opinions of the system
• Do not give the early breakthrough
• Compare the stories of some of the system against the same case
• Note the logical inconsistency problem

ENGINEERING INVESTIGATIONS

Direct:

• The questionnaire
• Frequently asked questions
• Observations

Indirectly:

• Flow of procedure

• Reviewing documents

• Sample

• Tabular

SYSTEM DESCRIPTIONS

At the moment found several descriptions about system, that is:

• Enter
• Exodus
• File
• Data elements
• Transaction volume and document action
• Data Flow Diagram (DFD)

ANALYSIS REQUIREMENT

Stage of intensive interaction between the systems analyst with the end user where the system shows the development team expertise to get feedback and trust so that the user get a good participation.

Four Purpose That Want Achieved:

• Explain the complete system

• Information system that describes the ideal

• Bringing information system to the ideal conditions at this time with attention to the constraints of resources

• Provide encouragement to the confidence in the system development

Method

• FAQ

• Quisioner

• Observation

• Procedure analysis

• Observation document

Constraints Of Resource

• Time

• Money

• Expertise

• Technology

• External factors

Analysis Document Requirement

• Landing analysis: Relationships with end users, the observation process, problems in data collection.

• The user needs: The need actual, reporting requirements, training needs and the influence of the new system.

• System constraints: Explain the constraints of time and cost, expertise, technology, and external factors.

• Documents such as data collection instruments, statistical consensus, the logical flow of data and physical, data elements in the initial data dictionary.

GENERATING SYSTEM ALTERNATIVES

There are several ways to approach the condition of the system at this time with the condition of the ideal system, namely:

• Creating an alternative to solve the problem of information system.

• Alternative is best applied wisely.

Options strategies that can be selected to apply, namely:

• Distributed versus centralized processing.

Changes in decision-making information from the centralized data processing to the end user Decentralized responsibility center

• Integrated versus dispersed database.

System designer must consider the data are entered in the database and enter the File

• Surround Strategy of System Development.

About important environmental strategy in the case of company takeovers because the information system of other companies may vary with the company at this time.

Choice Of Tactics

Selection is done before the design operational.

Designing Operational Options

Options can be grouped into:

Input

• Online Vs Off Line Data Entry

• Keyed Vs Machine Readable Data Entry

• Centralized Vs Decentralized Data Entry

Processing

• Batch Vs Real time record update

• Sequential Vs Direct Access to records

• Single Vs Multiple Users update of records

Output

• Traditional Vs Turn Around Documents

• Structured Inquiry Vs based reports

SELECTING THE PROPER SYSTEM

Compare tactics: systems based on the comparison of costs and benefits relative. There are 3 ways a system said the system is superior to the other if:

• A cost is lower than B and both are the same benefits

• A cost is lower than B and A yield advantage of more than B

• A and B have the same but the cost advantage generated a lot more.

Some Methods Comparison System,that is:

• Break Even point Analysis

• Payback Period

• Discounted payback period

• Internal Rate of Return

Cost Categories

• Hardware

• Software

• People

• Suppliers

• Telecommunications

• Physical sites

Cost Details

Comparing the cost of information systems through the life of the system, analysts projected how the cost changes for the future and there are 3 models cost information system, namely Linear, and exponentially Step Function

Cost information system can occur only once and can also occur on an ongoing basis.

• Cost information system that occur only once the cost on time and development costs that occur during the development of the system.

• Cost information system that occur continuously among reccuring cost and operational cost where the cost of this is the case when the operating system information every day.

FACTORS INTO INFORMATION SYSTEM

Qualitative factors that lead the performance information system that both of them

- Reduce errors
- Reduce the time to fix errors
- Reducing the response time from the workstation alternative
- Accelerating the provision of information
- Increase the security system
- Have active update source record
- Increase user satisfaction

FACTORS INTO CORPORATE STRATEGY

• Customer satisfaction

• Sales increased

• Consumer and vendor commitment

• Information marketing products
  

PRESENTING LEARNING SYSTEM

• Make short presentations

• Reduce the detail description techniques

• Clearly presented with visual aids

• If using a model using a tool such as a laptop so that more informative

• Emphasize the benefits of the proposed system with some alternative information that is appropriate conditions experienced by the company.

CONTINUING DESICION OR NOT

• If the company decided to develop the information system, the department will do next, namely the System Design Process.

• If then the System Development Life Cycle (SDLC) will be terminated.

• Often the problem will be found with the system and the study and top management will usually ask for the re-employment system to study.

• Model will describe some of the stages of the repeated and sometimes the information will make a decision before the repeat stage system of study.

• With the alternative, the decision to repeat a previous stage SDLC or not called Go - No-Go Decision.

REFFERENCE:

1. Slide Pengamatan Awal, Kebutuhan Analisis; Ngurah Agus Sanjaya ER, S.KOM, M.KOM

Development General Observation System

The Importance Of System Development

System development can mean to composed a system bew to replace system old ones as a whole or repair system that there. A system necessary developed and repaired, matters that causes system necessary developed, that is:

1. That troubleshoots existence at old ones system. That troubleshoot can be in the form of:
a. Problem.
The problem in this system can be in the form of deceits that causes not wealth treasure the safe companies and truth from data is less well guaranted, errors not intentional that causes data truth not well guaranted, the operation not efficient, and not bidding the management policy that applied.
b. Organization Growth.
Organization growth here that is information need more vaster, data processing volume more increase, bew accountancy principle change. Caused by this change, so old ones system not effective again, so that must there development towards system.

2. To reaches to chances.
Organization will begin to feel that this information technology necessary is used to increase the available of information so that can support in course of decision making that be done. In rivalry, information speed or time efficiency very determine success or not it strategy and plan that have been arranged to reaches to chances existing. Chances this can be in the form of market opportunities, increase the service to customer and other as it.
3. Instructions existence (directives).
Also can happen caused by instructions from higher and or.

The purpose of developing a information system

Caused by troubleshoot likes on, so system development is wanted to break existing troubleshoots, reaches to chances existing and fulfil instruction that given.

Supposed enhanceds in bew system development, that is:

1. Performance, enhanced towards performance system bew so that be effectiveer. The performance measurable from job total that can be done at the time of certain (troughput) and average time that delay between two transactions (response time). For example, before now a only can do a job in certain range of time, but along with age development, so that thing becoming not effective so that emerge willing to increase performance from system so that can do job more than one in certain range of time.
2. Information, enhanced towards information quality that presented. For example, with enhanced existence toward system, so a system before now has information inaccurate is a system that has information with far quality better with willing existence from admin to increase quality so that system be better.
3. Economy, enhanced towards benefits or profits or decreasing cost that. For example, a company use resource very much so that need cost and big investment to run system in companies. With case existence, so here be feeled to develop system so that system experience enhanced so that can depress cost that must be taked.
4. Control, enhanced towards control to detect and repair errors with deceits that. For example, a company has a big error when do a certain process, this evoke a problem when does process done continually. Therefore, here control toward system so that increased so that problem doesn't disturb work from the company.
5. Efficiency, enhanced towards information efficiency. Efficiency here relate to resource that used so that resource that use minimum may be. For example, here a company to use a ancient system for the marketing problem, that is by using sales. Here need enhanced toward system development so that resource that used (sales) minimum may be to depress expenditure by make a on-line system to market product companies.
6. Services, enhanced towards service that given by system. For axample, here a company has a system service manual by using labour. At one time, there are many customer, so that labour here in a dither to serve customer and customer even also felt not pleasant with the mentioned. Need development toward system that use so that customer felt pleasant with service that given. Here company can use system service that can serve customer swiftly and accurate.

System Development Principle

System development principles:

1. System that developed management.
2. System that developed big capital investment.
3. System that developed to need one who educated.
4. Work stage and duties that must be done in course of system development (System Development Life Cycle).
5. System development process must not massage.
6. Don't be afraid cancel project.
7. Documentation existence for guide in system development.

System Development Life Cycle

Waterfall Model



Waterfall Model explanation:

1. Requirement, in process requirement this is systems analysis does need collecting process from customer and or top management either from aspect area also business strategy, towards system and or desirable application.
2. Design, in this stage us does systems analysis process, fitur that need, need from application that be made good to also the application. Beside that, here we also begin to make design plan from system, like interfaces delegation, the data structure, the architecture, and as it.
3. Implementation, implementation process has been continuation from where did we begin to implementation design that made to into program codes that be read by engine language.
4. Verification, process verification here same like testing process towards system and or application that made. This process focus in internal logic from application that made, as certain that any line coding checking. Beside that here we also have done testing process towards possibility towards errors from system that made.
5. Maintenance, process maintenance here be repair process and maintenance towards system that made. Repair process here done when application and or system that made to experience error after to customer so that must necessary repair process towards system and or caused by development towards an OS so that application must be repaired again to be update.

Iteratif Model


Iteratif model explanation:

Iteratif Model here same with waterfall model, here found same processes, like requirement, design, implementation, and testing (verification).

1. Initial planning, be beginning planning process and or beginning ideas to make a system.
2. Planning, planning here be a thinking that ripe towards system that be made.
3. Requirement, same like in process requirement waterfall model, here systems analysis does need collecting process from customer and or management on towards system and or desirable application.
4. Analysis and design, in this stage us does systems analysis process, fitur everything that need, need from application that be made good to also the application. Beside that, here we also begin to make design plan from system, like interfaces delegation, the data structure, the architecture, and as it.
5. Implementation, implementation process has been continuation from where did we begin to implementation the design that made to into program codes that be read by engine language.
6. Deployment, process deployment here purpose has been distribution process towards system that made, in our meaning distributes before hand system to society before do testing so that we know our system deficit.
7. Testing, process testing here we have done testing towards system and or application that made. This process focus in internal logic from application that made, ascertain that any line coding checking. Beside that here we also have done testing process towards possibility towards errors from system that made.
8. Evaluation, process evaluation here be repair process, maintenance and renewal towards system that made. Repair process here done when application and or system that made to experience error after to customer so that must necessary repair process towards system. Maintenance process and renewal be done caused by development towards an OS so that application must be repaired again to update. In renewal process here will return to do process planning, data collecting (requirement), analysis system and design, implementation, deployment, testing and return again to evaluation. if there development again, so this cycle be repeated again.

Spiral Model



Spiral model explanation:

Spiral model is divided to be 4 task areas, that is:

1. Determine objectives, in this process us will determine what will be made system, either from also output from it system.
2. Identify and resolve risk, here we do identification process, planning and analyze risks may be happen. In identification process and planning, we must define before hand resource, time precision, and other related information project with system that we shall make. While in risk analysis process here we do analysis towards risks may be happen, between management or technical.
3. Development and test, in process development and test this is us do engineering process, construction and testing towards system that be made. In engineering process and construction, we do process coding to make a application. While in testing, we do testing process towards system or application that we have made.
4. Plan the next iteration, here we do iteration process for plan next and or evaluation in the event of request from customer in order to change towards system or application.

In this spiral model, when is process revolutionary begun, system engineer team moves clockwise surround spiral begun from the kernel. Spiral rotation first track produces development from product spesification. Spiral rotation furthermore may be worn to develop a prototype, and progressively develop system version will be increase. Each track that pass planning region produces to setting in project plan.

Approach System Development

Found several approach to develop system, that is:

1. Classical approach vs structured approach (looked at from methodology that used).
2. Piecemeal approach vs system approach (looked at from target that be achieved).
3. Bottom-Up approach vs Top-Down approach (looked at from manner determines need from system).
4. Total-system approach vs modular approach (looked at from manner develop it).
5. Great loop approach vs evolutionary approach (looked at from technology that used).

1. Classical Approach Vs Structured Approach

 Classical Approach

Classical approach is approach insides system development that follow stages at system life cycle without supplied with tools and techniques.
Troubleshoots that can emerge from approach classic, that is:

1. Software development will be difficult.
Classical approach less give tools and techniques insides develop system and as finally software development process becoming not directional and difficult to done by programmer.
2. Treatment cost or system maintenance will be more expensive.
The expensive treatment cost at classical approach caused system documentation that developed less complete and less structured.
3. Big error possibility system.
System not test during the development stage is principal source from system errors. Classical approach doesn't prepare to manner systems analysis to do testing system, so that system errors possibility will be bigger.
4. System success less well guaranted.
Emphasis from classical approach work from system developers staffs, not in system user. Because classical approach less involve system user in system development, so system user needs are less matching with the one which desirable and as finally system that applied less success.
5. System applications internal issue.
Because system user involvement under communication in system development stage, so only will know only in stage will applied. As finally system user will be startled and unaccustomed with bew system suddenly introduced.

 Structured Approach

Structured approach equiped with tools and techniques that wanted in system development, so that end result from system that developed be got system the structure will be defined well and clear.


2.Piecemeal Approach Vs System Approach

 Piecemeal approach
Piecemeal approach be to system approach development that emphasized at one particular activity or certain application. Activity that chosen, developed regardless of the position at information system or regardless of overall target from organization.

 System approach

System approach pays information system as one integration unitary to each activity or the application. This approach also emphasized in overall goal achievement from organization, not only in that information target.

3. Bottom-Up Approach vs Top-Down Approach

 Bottom-Up Approach

This approach 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 be feature classical 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.

 Top-Down Approach

This approach on the contrary begun from level on organization, that is begun with define target and organization policy. Step furthermore from this approach melakukannya 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 desicion 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.

4. Total-System Approach vs Modular Approach

 Total-System Approach

Total-system approach to be approach develop system together according to comprehensive. This approach less synchronized for complex system, because will be difficult be developed. This approach be feature classic approaches.

 Modular Approach

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

5. Great-Loop Approach vs Evolutionary Approaches

 Great-Loop Approach

This approach apply 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

This 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 Methodology

Methodology is methods unitary, procedures, job concepts, rules and postulates that used by a science, art or discipline the other. Method is a manner, systematic technique to does a certain. System development methodology means methods, procedures, job concepts, rules and postulates that be used to will develop information system. Algorithm is sequence procedure to break a problem.
Classification based on existing methodology can classified to be three, that is:

1. Functional decomposition methodologies.
This methodology emphasizeds in solution from system into subsystems smaller, so that easier to be understood, designed and applied. Belong this methodology, that is:

 HIPO (Hierarchy plus Input-Proccess-Output)
 Stepwise Refinement (SR) or Iterative Stepwise Refinement (ISR)
 Information-hidding

2. Data-oriented methodologies.
This methodology will emphasized in characteristics from data that be processed. This methodology can be grouped to into two class, that is:

a. Data-flow oriented methodologies.
This methodology is based in solution from system intoes modules based on data element type and module logic behaviour insides system. Belong in this methodology, that is:
 SADT (Structured Analysis and Design Techniques)
 Composite design
 Structured System Analysis and Design (SSAD)
b. Data structure oriented methodologies.
This methodology emphasizeds structure from input and output at system. Belong this methodology, that is:
 JSD (Jakson's System Development)
 W/O (Winner/Orr)

3. Prescriptive methodologies.
This methodology is usually is provided by software maker factory. Belong in this methodology, that is:

 ISDOS (Information System Design and Optimization System)
 PLEXSYS
 PRIDE
 SDM/70
 SPECTRUM
 SRES and SREM
 Chapin's approach
 DBO
 PAD
 HOS
 MSR
 PDL

Tool In System Development

Tools that used in a methodology usually shaped a picture or diagram or graph. Graph formed system development tools, that is:

 HIPO diagram
 Data flow diagram
 Structured chart
 SADT diagram
 Warnier/Orr

Beside graph formed tools, found several graph formed tools has general likes Chart. Chart can classified as follows:

1. Chart to describe activity (activity charting).
 System flowchart
 Program flowchart that can be in the form of:
 Program logic flowchart
 Detailed computer program flowchart
 Paperwork flowchart or form flowchart
 Database relationship flowchart
 Process flowchart
 Gantt chart
2. Layout charting
3. Staff relatioanship charting
 Working distribution chart
 Organization chart

Technique In System Development

Techniques that can be used in development system, that is:

1. Project management technique, that is CPM (Critical Path Method) and pert (program evaluation and review technique). This technique is used for project scheduling.
2. Fact finding techniques, that is technique that can be used to gather data and find facts in study existing system, that is:
 Interview
 Observation
 Questionnaire
 Sample collecting
3. Cost-effectiveness analysis or cost benefit analysis
4. Technique to run meeting
5. Technique inspection/walkthrough.

Analysis System And Programmer

Analysis system is one who analyze system to study and identify that problems and determine user needs system. Programmer is one who write program code to a certain application based on has planned to get up that made by system analyst.
Function and or task from a analyst system that is as mediator or liaison between system user with programmer. Analyst system must realize right second knowledge differ about the computer technology to can communicate with programmer and knowledge about application that be developed so that can communicate with system user.

Knowledge And Skill That Need System Analyst

Found several vast eruditions and skill that must has by a system analyst, that is:

1. Knowledge and skill about data processing technique, computer technology and computer programming.
 Technical skill that must has belong skill in tool use and technique for application software development with skill in use computer.
 Technical knowledge that must has cover erudition about hardware, data communication technology, computer languages, os, utilities, and another.
2. Knowledge about business in general.
This knowledge be wanted so that system analyst can communicate with system user.
3. Knowledge about quantitative method.
System analyst use many quantitative methods in build application models, like dynamic programming, regresion, network, decision tree, trend, simulation and other as it.
4. Trouble-shooting skill.
System analyst must has ability to put complex troubleshoots that is faced by business, divide problem into parts, analyze it and then must can return composed to be a system can overcome troubleshoots.
5. Communication skill delivers staff.
System analyst must has ability to hold communication either through tongue or article. This skill is need in interview, presentation, meeting and report maker.
6. Skill builds connection delivers staff.
Human is factor critical insides system and human character one with another differ, so that need a skill to build connection delivers staff.

LIBRARY

HM, Jogiyanto. Analisis & Desain Sistem Informasi. Yogyakarta: ANDI,2007.
Roger S. Pressman, Ph.D., Rekayasa Perangkat Lunak, Buku Satu.Yogyakarta: ANDI.