Ririn Ilkom '06

ERD NORMALIZATION

2009-05-03T21:44:00.008+07:00

the proses of normalizazion diagram is:

The initial table

Functional Depedencies

Normalization 1 NF
Normalization 2NF
Normalization 3 NF

Normalization

2009-04-25T21:53:00.014+07:00

The design database is required, so that we can have a database of compact and efficient in the use of storage space, quick and easy in the initialization manipulation (add, change, delete) data.

Database design process

Gather user needs / business
Develop a needs-based ER Model user / business
Convert E-R model to the set of relations (tables)
Normalization relations, to remove anomalies
Implemented to create a database with a table for each relationship that is normal

Database normalization

Normalization process is the establishment of the database structure so that most of the ambiguity can be removed.
The process of normalization is the process of grouping data elements into table-table that entity and show relationship. In the process of normalization is always tested in some cases, if there are difficulties at the time to add / insert, delete / delete, change / update, and read / retrieve on a Database .Normalization stage, starting from the most mild (1NF) to most stringent (5NF) .Usually only up to the level of 3NF or BCNF because already sufficient to generate the table-a table of good quality.

Normalization must be done because:

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:

If there is decomposition (decomposition) table, it must be guaranteed safe decomposes (Lossless-Join Decomposition). That is, after the table is described / decomposed a new table-table, the table-table can generate a new table with the same exact.
Maintain dependence on the functional changes in data (Dependency preservation).Does not violate Boyce-Code Normal Form (BCNF)
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).

Normalization Stage

The process of normalization

Data described in the form of a table, then analyzed based on specific requirements to some level.
If the table has not been tested to meet specific requirements, the need to table some of the table into a more simple form to meet the optimal.

Functional Dependency

Functional Dependency describes a relationship attributes in relation
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.
reads determine the functional
notation : B --> A
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 not 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 of the table value
Name-->Nrp
Because for each value Nrp the same, then the value of the same name
(Mata_kuliah, NRP) -->
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).
NRP not Mata_kuliah
Value not NRP
FIRST NORMAL FORM (First Normal Form - 1NF)

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

Many attributes of value (Multi valued attributes).
Attributes composite or a combination of both.

So:
Price is the domain attribute must be atomic rates

Example (1)
E.g. Student Data as follows:

Or

Table-the table above does not meet the requirements 1NF
Example (2)

Decomposition becomes:
Student Table:

Table Hobbies:
Second NORMAL FORM (Second Normal Form - 2NF)

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 dependence (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

Y is full if it is said to delete anàFunctional dependency X attribute A from X means that Y is no longer dependent functional.
Y said if deleting a partial attribute A from X means that Y is functionally dependent.àFunctional dependency X
R depend on the full primary key fungsioanl R.ÎRelation scheme R in the form 2NF if every non-primary key attribute A

Example (1)
The following table meet 1NF, 2NF, including but not

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

Example (3)
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) --> Student Table
fd3 (KodeMk, Matakuliah, SKS) --> MataKuliah Table

NORMAL FORM Third (Third Normal Form - 3NF)

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).
Example (1)
Table following students eligible 2NF, 3NF, but does not meet

Because there are non-primary key attribute (i.e., City and Provincial), which has a dependence on non-primary key attributes of the other (i.e. KodePos):
(City, Province)àKodePos

Example (2)
So that the table should be decomposition:
Student (NIM, NamaMhs, Road, KodePos) r>KodePos (KodePos, Province, City)

Example 3
A model data meets said third normal form if it meets the form of both normal and does not have the attributes of non-identifying (non-unique identifier) that depending on the attributes of other non-identifying. If there is, separate one of these attributes a new entity, and attributes that depend on the attributes to become the new entity.
In a simple data model that we use here, none of non-identifying attributes (such as Task Mata kuliah description, or name Lecturer), which depends on the attributes non identifying other. But for the sake of example, we have Lecturer e.g entity attributes information Home Address and Phone Number House. Both can not be unique identify the object of a certain entity Lecturer, but both are mutually dependent.
As in the previous two-step normalization, as this type of dependences
can be removed by creating a new entity (which will not be created because the three
entities have been enough for one article).
Last model that we can meet this third normal form (third normal form)
and ready to convert into a table. But before, we need to discuss the various types of
relations, which are often found in data modeling, including those we met in the example model
data this time.

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 Normal once and forced each of the attributes depends on the function in the super key attributes.
In the example below there is a relationship seminar, is the Primary Key NPM + Seminar.
Students may take one or two seminars. Each seminar requires 2 each of the students and led by one of the 2 seminar. Each leader can only take one seminar course. NPM in this example and show a Seminar.

Relations Seminar is a form of Third Normal, but not BCNF
Seminar Code because the function depends on the Pembimbing, if any Pembimbing can only teach a seminar. Seminar depend on one key attribute is not as super disayaratakan by BCNF. So
Seminar relations must be parsed into two namely:

Normal form of the fourth and fifth

Relations in the fourth normal form (NF 4) if the relation in BCNF and dependency tdak contain many 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.
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.

DATABASE AND ER-Diagram

2009-04-19T12:06:00.006+07:00

DEFINITION Database

Definition of the database:
A set of data stored in the magnetic disk, optical disk or other secondary storage Collection of integrated data-related data of an enterprise (company, government or private) Is a system which consists of collection of the file (table) in a database in a computer system and a related set of data base management program (DBMS: Database Management System) that allows several users and / or other programs for acess and manipulate files ( table-table) is

for example:

Manufacturing companies have data in form of production planning data,actual production data,cmaterial ordering data

The hospital has a patient data form of data, doctor, nurse, etc.

DATABASE MANAGEMENT SYSTEM (DBMS)

definition
Collection / database combined with software applications that are based database 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.

Benefits of DBMS

Reducing the repetition of data.
Achieve independence of the data.Specification data stored in each application program.Changes can be made on the structure of data without affecting programs that access the data.
Integrating data from multiple files.When the file was so provide a logical connection, the organization is no longer a physical constraint.
Retrieve data and information quickly.Relationships logical query language allows users to take data in seconds or minutes.
Increase security.Both DBMS Mainframe and micro-computer can include multiple layers such as password security, user directory, language and a password.

Losses DBMS

Obtain the expensive software.
Obtain the configuration of the hardware.
Need for DBA and retain staff.

BIT, BYTE, Field
Data bit is the part that contains the smallest value of 0 or 1
Byte is a set of bit-bit similar with the same 1 byte with 8 bits
Field is a set of byte-byte similar, in the database used the term attribute

ER Diagram Components

Entity
Attribute
Relationship (between entities):
Relationship types
Role
Cardinality

Attribute / Field

It is the nature or characteristics of an entity that provides provide detail on these entities.
For example
an employee has a name, SSN, address, gender, date of birth.
One entity will have specific values for each attribute
For example
a particular employee has the name John Smith, SSN: ... .. Address: Sex: Birthdates: January 5 55
each attribute has a set of values associated with it.
This value is a set of data types, such as integer, string, and the other,
And can also be given a certain range, e.g., date of birth of employee
A relationship can also have attributes
TYPE-TYPE Attribute
Single vs. multi value
Single
can only be filled at most one value
Each entity has a single atomic value
Example: SSN, Sex.

Multi value
can be filled with more than one value with the same type of
an entity can have multiple values
Example:
Color of a CAR
Degree of employee
Expressed as: (color), (title).

Atomic vs. composition
Atomic
can not be divided into the attributes of smaller
Composition
is a combination of several attributes of a smaller
Example:
Address (Apt #, House #, Street, City, State, Zip Code, Country)
Name (first name, Middle Name, Last Name).
The composition can be a hierarchy where the attribute is also a component of composite attribute.
Derived attribute
attribute value can be derived from other attribute values,
e.g. age resulting from the date of birth attribute

Null Value attribute
Attributes that have no value to a record
attribute can have a null value if:

Not applicable, e.g. the name for the couple people who are not married
Missing: The value but there is not yet known. E.g. high body someone.
Not known: You do not know if the value is there. E.g. home phone number.

Mandatory attribute Value
Attributes must have values

RECORD / TUPLE
It is a line of data in a relationship
Consists of the set of attributes where the attribute-attribute-attribute is to inform each other entity / relationship fully
Record is a collection of field-field is structured in a format that has been determined.
During the design of the system, records will be classified as fixed-length records or variable-length record.

Entity / FILE
File is a collection of similar records and have the same elements, the same attributes but different data value
A entities is an "object" (thing) or "object" (object) in the real world that
can be distinguished from all other objects. Entity sets are a set of entities
have the same type. This type of similarity can be seen from the attribute / property that
owned by the individual entities. E.g., group of people who save money on a
bank entities can be defined as a set of customers

File Type
In processing applications, files can categorized as follows:

Master File
Transaction File
File Report
File History
File Protection
Job File

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

Element KEY DATA

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 . selection key attributes is important in the design of the database because:

to affect validation of data integrity and performance database
With declare an attribute as the key and declare 'not allowed duplicates' will prevent the user entering the same data that is not desired
A key will be how to maintain the integrity of the key with another key on the table.

Elections key attributes:

Key is an attribute that does not change. Example: SSN, employee_ID, SKU (stock-keeping-units), license plate number.
Key values can not be null, must have a valid value. Example: Date of students is a bad choice to be a key.
Avoid the key that has a certain intelligence or codes built in. Examples: building codes (which can be changed later)

SPECIES OF KEY

Super key is one or more attributes of a table that can be used to identify entity / record of the table are unique (not all attributes can be super key)
Candidate 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 super key 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 following criteria:

Key is more natural to use as reference
Key is more simple
Key is guaranteed unique

Alternate Key is an 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 cardinalities one to many (one to many) or many to many (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
DFD is a model of network functions that will be implemented by the system
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 form of a rectangle. Entity is something that exists in the real system and the abstract where the data stored or where there are data.
Relationship
ER diagram on the 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 relation.
A relationship connecting the two / more different entity with a specific meaning.
Example:
EMPLOYEE John Smith works on the ProductX PROJECT
EMPLOYEE Franklin Wong manages the Research DEPARTMENT.

Type relationships that are grouped together into a single type. Example:
WORKS_ON relationship type in which employees participate and PROJECTS
MANAGES relationship type in which employees participate and Departments.

Degree of relationship

is the number of entities participating in a relationship. Degree which is often used in the ERD.
Unary Relationship
model is the relationship between the entity originating from the same entity set.
Binary Relationship
model is the relationship between 2 entities.
Ternary Relationship
is a relationship between the instance of 3 types of entities are unilateral.
Cardinalities
tupel indicates the maximum number that can be relation with entities on the other entity

There are 3 cardinalities 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 seen .for an incident on the first entity can have any relationship with more incident on the second entity, if the one incident on the entity the second can only have one relation with the incident on the first entity.

Many To Many: if any incident occurs in an entities have relationships with other entities in the incident.
reference
Elmasri & Navathe, Fundamental of Database Systems, 5th Edition, Chapter 1, 2007

DATABASE and ER-DIAGRAM persentation of NGURAH AGUS SANJAYA ER, S.KOM,

Data Flow Diagram

2009-04-04T22:14:00.003+07:00

Definition

DFD is a logical data model or process that is made to describe the origin of the data and the destination where the data out of the system, where data is stored, the process that produces the data and the interaction between the data stored and the process is imposed on data.
DFD are often used to describe a system that already exists or the new system will be developed logically without considering the physical environment where the data flows, or where data are stored and the user is less easy to understand to understand the field of computer systems that will be done.

Context Diagram

the top level diagram, a diagram of a system that describes the stream-flow data that enter and exit the system and the incoming and
out of the foreign entity
The case must be considered:
Provide a snapshot of the entire system
Terminals that provide input to system called source
Terminal that receives the output called sinks
Only one process
Consists of a process and describe the scope of a system
Is the highest level of the DFD that describes the entire system to the input of the system and output
System is limited by Boundary (depicted by broken lines)
No storage (storage)
how to create a context diagram
Specify the name of the system.
Determine the limits of the system.
Specify the terminator is present in the system.
Define what is received / given terminator from / to the system.
Describe context diagram.

Zero Diagram

After making context will proceed with the making of:
DFD level 0 context diagram is a representation of more detailed (overview diagram) and to give a view on the overall system in which, showing the main function or process that is, the flow of data and entity external
It should be:
At this level of data storage possible
To process that does not detail again on 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

how to create a zero diagram:
Determine the main process in the system.
Determine what is given / received each process to / from the system while considering the concept of balance (the data flow outgoing / incoming from a level should be the same as the flow of data entry / exit to the next level).
If necessary, store a feature data (master) as the source and destination flow data.
describe diagram level zero.
- Avoid intersection flow data
- Give the number on the main process (the number does not indicate the order process).

Detailed Diagram

is diagrams that decompose a process that is in the diagram zero level or above
Numbering level in the 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

DFD level 1:
Each process level 0 will described the details must be observed:
�� balance the flow of data between zero diagram and detailed diagrams In the process

�� not detail again, add a sign * at the end of the numbering process Balance

�� data store used
How:
Define the process of smaller (sub-process) from the main process in the zero level.
Determine what is given / received each sub-process to / from the system and note the concept of balance.
If necessary, store a feature data (transaction) as the source and destination flow data.
One describe level DFD
- Avoid intersection flow of data.
- Give the number on each sub-process that shows the decomposition of the process before.
Example: 1.1, 1.2, 2.1

SPECIFICATION PROCESS

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

ON FOREIGN (foreign entities)

Foreign entity is the entity that is outside the system that provides data to the system (source) or receive information from the system (sinks) that are in the outside environment that will provide input or receive output from the system. Foreign entity is not part of the system, when an information system designed for one section / department and other parts that are still related to a foreign entity. While the terminal is the entity that is part of the system.
Something that is outside the system, but it provides data in the system or to provide data from the system
for example:
- An office, department or division within the company but outside the system being developed.
- The person or group of people in the organization but outside of that system is being developed.
symbolized with the notation
External entity not part of the system including
Naming:
The name of the form of noun
Terminal may not have the same name except the same objeknya

CASH DATA

Is the place to make a flow an information
Depicted with the straight line that connects the components of the system
Data flow direction is indicated with arrows and lines give the name on the flow of data that flows
Flow data flow between processes, data storage and data flow indicates that the form of data input for the system

Data flow describes the flow of data from one entity to another entity. The direction the arrow depicts the flow of data. There are several streams of data, namely:
• Between the two processes in sequence
• from data storage (data store) to the process and vice versa
• From the source to the process
• From the process to sink

Guidelines of the name:
Name of the flow of data that consists of some words associated with the flow lines connect
No flow data for the same and the name should reflect its content
The flow of data that consists of several elements can be expressed with the group element
Avoid using the word 'data' and 'information' to give a name to the flow of data
Wherever possible the complete flow of data is written
Other provisions in the current data:
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
Data flow into or out of data storage does not need to be given a name if:
The flow of data simple and easy to understand
Describes the data flow of all data items
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 a process

PROCESS

Describe what the process done by the system. Transform function of one or more of data input into one or more of the output data in accordance with the desired specifications. Each process has one or more data inputs and generates one or more output data. The process also often called bubble. For Physical data flow diagrams (LDFD), the process can be done by a person, machine or computer and for Logical data flow diagram is a process only shows the process of computer
Symbols used: circle
Guidelines of the process:
Name of the process consists of a verb and noun, which reflects the function of the process
Do not use the process as part of the name of a bubble
May not have some process that has the same name
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

Data Storage

Data storage is a storage place for data that exists in the system
symbolized with a pair of parallel lines or two lines with one side open side
The process can retrieve data from or provide data to the database
Savings can be the following data:
1.file or database in the computer system
2.manual record keeping or
3.the data in a table
4.table reference manual
5. agenda book
Guidelines of the name:
The name should reflect the data storage
When his name more than one word must be marked with the number

DFD Symbols

Dictionary of Data (Catalog Data)

Is a catalog (storage) of the elements that are in a system. Data dictionary has the same function in modeling the system and also help the system to understand the application in detail, and organize all elements of the data used in the system so that users and analyze system have basic understanding about the same input, output, storage and processing.

Data dictionary defines the data elements with the function as follows:
1. Explain the meaning of the data flow and storage in the DFD
2. Describe your composition package moving through the data flow to be described, for example address city, state and zip code
3. Describe your data storage composition
4. Specify the value and the relevant unit for the storage and flow and
5. Describe your relationship between the details of storage that will be the focus point in the diagram entity relationship

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 process
At analysis, the data dictionary is used as a means of communication between the systems analyst with the
At the system design, 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:
Name of data flow: must note that readers who need further explanation about a flow of data can find it easily
Alias: alias or other name of the data can be written when there is
Forms of data: used to segment the data dictionary to use when designing the system
Flow data: indicates from which data flows and where the data
Description: to give an explanation of the meaning of the data flow

Balancing IN DFD

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
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
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
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 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 same object

Restrictions in DFD

Flow data may not be from outside the entity directly to other outside entities without going through a process
Flow data may not be from the savings directly to the data to outside entities without going through a process
Flow data may not be saving the data directly from the savings and other data without going through a process
Flow data from one process directly to the other without going through the process of saving data should / be avoided as much as possible

Initial Investigation and Requirement Analysis

2009-03-28T16:13:00.000+07:00

Initial Investigation

Problem (problem) is inequalities gap between the goal system and the actual system conditions, with the understanding why other systems failed to achieve the goals that the system has been determined previously. To know the things that have been what caused the failure of the system, and then an analyst should do more investigation before take action to improve the system. With the investigation, an analyst will better understand the problem and the flow system further, detect even in the already known problem but the problem still describes the size of the course.
Many reports in the detection problem may not actually be real or cannot be solved. This may be because:
a. Goals that are too difficult or the ideal so that might not be reached.
b. The system cannot be developed because of lack of resources, attitudes or both.
c. Measurement system that is not accurate.
d. Statement of purpose of the system that is behind (statement of goals is dated).
e. The gap between the ideal system and the system at this time is while (the gap between the ideal and the current system is temporary and will decrease given patience).

In solving the problem, should provide an explanation of:
a. explain condition of the system that runs through the investigation in detail.
b. Getting a consensus that the ideal system.
c. Develop alternatives to reduce some of the differences (gaps) between the ideal system with which the system is running.
d. Selecting the best alternative and sell it to management.

Task start point b to d will take a very long time, including cost is required. The objective of the investigation is to stabilize or indicate a problem that actually occurs in addition as a way
an analyst to understand the system in depth.

Constraints in the system of investigation

in doing some investigation, there are obstacles or constraints that will occur, among other issues:
a. Time (time)
Analysts lack of resources (resource) time, so only do part of the investigation. Usually time-related problems cost is required.
b. Cost (cost)
often the costs incurred related to the length of time for investigation activities, so that management will give the limits of cost.
c. Science (knowledge)
Manager information systems tend Junior told analysts that have not been have the technical expertise or knowledge is sufficient, so that will be impact on the results of investigations that are less deep, mature or complete.
d. Politics (politics)
Management or the parties may distribute certain issues which purpose is to restrict the investigation activities.
e. Interference (interference)
there are parties who try to intervene or investigation in activities that will disrupt or cause
chaos.

Recommendations

Results of the investigation is a recommendation, which is one of them as follows:
a. Does not take any action because it found no problems.
This can happen as they may in the preliminary report, problem is contrived so that the investigation conducted at the time of issue the problem does not happen or was not found.
b. Perform system maintenance for problems that small.
Maintenance of the system that made every day (short period) will be help minimize the problems that arise so quickly to and are always treated well.
c. Or improve skills in the run or the user
using information systems.
d. Consider modifications to the system in total, so the need to
thought to replace it with a new system.
e. Place going into the development plan system which is done immediately.

Strategy of Investigation

the strategy is needed for investigation to discovering the problem and to knowing caused the problem.
There are strategies of investigation it can be done, the several as follows:
a. Listen, do not lecture).
If you know all the answers, you definitely will not conduct investigations.
So that in the investigation should provide enough time management or for the user to explain in full and systems analyst and clearly do not dominate the discussion.
b. Do not provide solutions to the initial problem
This means do not try to show ideas to solve the problem, before the investigation is complete all the activities carried out, so avoid solutions that part-part.
c. Compare stories
Different people mean different views of the same problem, so the need to involve the supervisor and subordinate in the view of the problem clearly and can be trusted. Should not 1 from a source so that there is only 1 view (opinion).When the user has a difference of views, should find the difference and then seek the views that have similarities.
d. Note the reluctance responses (look for reluctant responses).
Reluctance to give responses that indicate something is hidden.
Too many problems be able the system causes confusion, so not able to explain in full.
e. Probe for logical inconsistencies).
Inconsistency is the logical termination of the data flow where data missing, or suddenly appear certain data. Some of the things that dealing with this issue:
There are data entered but no output (black hole).
There is the output (output), but no data entered (miracles).
f. Notice the impact you (observe your effect).
Given the differences of when you attend and when you do not present. Assessment is called directly with the internal probe. While external probe is that the assessment be done without anyone (searching external materials), such as by analyzing the report, history the problem tools, and sources of other secondary investigation.
g. Require hard work, giving rise to boredom (expect hard, boring work).
Be a detective professionals and patient in dealing with problems step by step and system is sustainable.
h. Avoid politics
Mission analyst system is not the judge the facts (your mission is the fact, not judgment).

Technical investigations
Investigation techniques included:
a. directly (direct (internal) probes)
namely to find out directly what is happening in the environment users. They allow you to pay attention directly without through certain parties (interpreter). Internal probes are source of chaos (disruptive), the differences arise because of attitude. Internal probes used as a richer and the justifier of facts that occurred (truer group of facts). There are three techniques for conduct the investigation directly, with:
* Questionnaire (questionnaires).
This technique is very appropriate, if in the investigation have constraints time and cost although to get it through the form of responded field. The things in the condition of the questionnaire will be the explanation different if carried out directly in the face (face to face interview). This is the best of the questionnaire as a document that can show differences that occurred in the respondents.
* Frequently asked questions (interview).
These activities require time and special expertise. Not all people able to interview successfully. Interview can be used for a sequence of questions in depth in addition to more flexible accordance with the condition of the field. Obstacles faced and the time is special expertise.
* Observation (observation).
It is a strong internal probe (a powerful internal probe).
Sit together with the system by making observations with the question is more specific.
Why you do this activity?
or where this document will be moved?. Each question may will be able to demonstrate problem-solving mysterious.

b. Indirect (indirect (external) probes)
Activities that can be done quickly and not visible from operational personnel, so that they can know the outside or something hidden from the user community. This activity will dominate
activities at the beginning of the SDLC, the internal probe to deepen.
* Flow of the procedure (procedure flow).
An operational procedure is the means (vehicles) for new employees
understand their work and experience to handle employee problems.
If the procedure does not flow properly, the system information cannot be
also operated correctly. Use the system flowchart for
the path information as an explanation Operating procedure.
If there is any problem procedure, the problem may be
arise in the actual operations.
* Reviewing documents (document review).
Is to find and collect the documents necessary
(critical document). If problems occur in many customer orders,
collected from the original source document customer orders that
used as its data-entry, interactive screen format, detail
transactions, and summary reports that the error occurred.
Documents often caused problems.
* Sampling (sampling).
Maybe you need information from the vendor that has been billing
provide discounts at the time of payment, because the company lost
money when the discount is not given when the delay of payment.
Example:
You can involve the customer to get the payer
information (although there are many transactions). Finally you can make
list of sample data with the random selection for one last Sunday,
select the 20 pages of daily transactions, select 5 items from each
page are selected., record the information for each item and 5
calculate the average-Ra and variants to the sample-sample of all transactions
payment occurs.
* Tabular (Tabular tools)
Also called the matrix, the check list (checklists) to find

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 (to update)
documentation systems that are running. Therefore, analysts improve document
system for investigating the problem.
Description of the system include a clear explanation at this time:
a. Inputs (inputs)
b. Outputs (outputs)
c. Files (files)
d. Data elements (data elements)
e. Volume of transactions and documents action (transaction and document action
volume)
f. Data flow diagrams (data flow diagrams)

Requirement Analysis

Requirement analysis phase is the intensive interaction between the analyst
system with the user community the system (end-user), where the development team
system shows the expertise to get the responses and confidence
the user, so get a good participation.
Is working hard to get agreement (skeptical) users about their needs from an information system, as they may the failure of the previous information system.

In doing this step will be achieved 4 goals, namely:
a. Describe the system at this time in full.
b. Describes the ideal information system.
c. Bringing information system to the ideal conditions at this time with
attention to resource constraints.
d. Provide encouragement to the confidence of this team into the development system.
The desire of users is:

Requirement in the first stage of the system is doing a survey of
the desire and the information system that is ideal.
Here is an ideal concept than a reality, meaning that no
the ideal system (no system is perfect information) but are
subjective. If this is not explained in depth can
rise to differences of views will be disappointing or end-user.

Method needs analysis

Keep the selection method of collecting data for the right to
system requirement. Methods are interviews, questionnaires,
observation, analysis procedure, and document the survey.
Each method will be described in depth as follows:

Frequently asked questions (Interviews)

1. How do the methods used.
Elections potential interviewees. Make arrangements to potential interviewees.
Setting up the structure of the complete and clear.
Choosing a person who will be interview in private and recorded.
2. Target of the method.
Private key in the process of DFD.
Sometimes involving outsiders, such as customers or vendors.
3. Benefits of the method.
Interviewer can measure the response through the questions and to adjust them
according to the situation that occurred.
Good for the problems that are not structured, such as why you
think this could happen?.
Shows the effect of interviewer time.
Show a high response since the preparation meeting.
4. Loss method.
Takes time and costs that are not small.
Requires special training and experience of the interviewer.
Difficult to compare the interview because natural subjectivity.
5. When both methods are used.
Obtaining the views or explanation of key personnel.
Test the credibility of the interviewees.
Search for the interview contradictions.
Stabilizing credibility team.

Some important factors in both the interview, namely objectives,
audience, format, weighting and combining responses, and documentation.

Questionnaire
1. How do the methods used.
Design using a standard questionnaire.
The questionnaire sent to a work environment end-user.
Summarized the structure of the response distribution in statistics.
2. Target of the method.
All end-users with him /his knowledge will be involved in the process of solution splitting system.
End-user associated with the use of symbols in a DFD.
3. Benefits of the method.
Cheaper and faster than the interviews.
Does not require a trained investigator (only one expert who needed to design a questionnaire for end-user is selected.
Easy to synthesis since the creation of the questionnaire.
Can easily minimize the cost for all end-users.
4. Loss method.
Cannot make a specific question for the end-user.
Analysts involved so that an impression can not reveal personal end-user.
Response to a low not because there is a strong encouragement for return the questionnaire.
Cannot adjust the question to end-user specific.
5. When both methods are used.
Simple question, and have no meaning fork.
Requires a broad perspective of the end-user.
When you have less time and cost.

Observation (Observation)
1. How do the methods used.
Personally visit the location of one analyst observed.
Analysts recording events in the location of the observation, including the volume and
processing, spreadsheets.
2. Target of the method.
The geographical location of the process shown in the DFD (Data Flow Diagram)
3. Benefits of the method.
Obtain records of the facts (opinion).
Does not require construction of a question.
Does not disrupt or hide something (end-users do not know
that they are observed).
Analyst does not rely on verbal descriptions of end-users.
4. Loss method.
If seen, analysts may change operation (end-user was observed).
In the long term, the fact that in one observation may be
not appropriate (representative) in daily or weekly.
Requires experience and special kehlian analyst.
5. When both methods are used.
Require quantitative descriptions, such as time, volume and so forth.
Suspicion that the end-user to the actual occurrence of a
does not occur (contrived).

Tip in the practical observations:

a. Do not be observed in a long time.
There are two reasons, namely: with a long time will disturb the operation which is being observed, and will deflect the real problems.
b. Create a brief note.
Before observation, please let the supervisor and the involved
about what will be done and why, so that will be
reduce interference.
d. Use a short checklist of the required information together.
e. Do not make observations without a plan ..

Analysis procedure (Procedure Analysis)
1. How do the methods used.
With operating procedures can identify and learn
document the flow of key information through the system, with data flow
diagram (DFD).
Each flow of the document describes the key system operating procedures.
Through observation, learn the reality of the analyst describe your
volume of distribution (high, low, moderate), and what next
done to a copy of the original document.
2. Target of the method.
Documents in the main DFD (Data Flow Diagram) Process in the DFD.
3. Benefits of the method.
Evaluation procedure can be done with the intervention (interferences)
is minimal and does not affect the operation.
The flow of the procedure can become a checklist for the structure
make observations.
4. Loss method.
Procedures may not be complete and not up to date again.
Learning the flow chart document requires time and expertise analyst.
5. When both methods are used.
Decide whether the failure of the system can help design good.
Analyst team is not completely familiar with the document flow.
Describe your document that disrupt the flow of work function.

Observations document (Document Survey)

1. How do the methods used.
Identifying key documents and reports (physical data flow diagram).
Collect copies of actual documents and reports.
Each document or report, is used to record data, including
field (the size and type), frequency of use and structure code (coding structure).
2. Target of the method.
The flow of key data shown in the data flow diagram (DFD).
3. Benefits of the method.
Minimize interruption of operations functions.
The beginning of the data element dictionary.
Often, major modifications may consider procedural.
4. Loss method.
Need enough time (there is a business organization in the
swamped with documents and reports).
5. When both methods are used.
Be done if a system will be designed (for activities
analysis, clarity in the new system design and analysis
documents can help to determine the next task of the design).

Sampling can help reduce the time and cost. Need for accuracy
select a sample of the population, so the statistics that require expertise
not experience a failure or threat.

Resource constraints

a. Time
substitution a system must be expressed in the framework since
decreasing function of the system quickly. Time constraints can be
influence the analyst to consider the technology innovation that is not
may be operated in a short time. Therefore, the need to
need enough time to have a leeway of time so that
can create an alternative to the most good.
b. Money
The ideal information system would require the expensive cost, so that
requires adequate funding. This will occur due to
competition with our competitors where they embed investment
in a large information system.
c. Expertise.
Staff information system may not have knowledge or experience
a significant problem, such as telecommunications, database integration, and
interactive setting. Companies can contract consultant to
increase design capabilities. This will be the opposed
constraint costs incurred for energy consultants.
d. Technology.
Technology needs may become the main problem in supporting
working system, so the need to pay attention to the development of technology continues
again, the consequences of going in cost and
not until the technology used behind the competitors.
e. Ekternal factors.
Many obstacles that come from outside of the design settings, such as prevention
use exotic technologies (of exotic technologies), to prevent
keep local data in a central database system, and so forth.

Needs analysis document

1. Referral (conduct) analysis.
Relationships with end users.
Analyze the records, forms and reports.
Observation process.
Analyzing the methods used.
Problems in data collection.
2. Needs of the user.
What are the actual needs.
Reporting needs (type and frequency).
Training needs.
The influence of the new system.
3. Constraint system.
Explain the constraints of time, cost, expertise, technology and factor
external.
Realistic system.
4. Documentation.
Instrument data collection (needs questionnaire, interview).
Consensus statistics.
The logical flow of data and physics.
Initial element in the data dictionary.
Generating SYSTEMS ALTERNATIVES
How do I approach the condition of the system at this time with the condition of the ideal system?
Creating an alternative to solve the problem of information system
Best alternative is applied wisely
Options Strategies
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 data base and the entrance to the File
Surround System Development Strategy of
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.
Generating SYSTEMS ALTERNATIVES
Options strategy
Selection is done before the design operational
Designing Operational Options
Design 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 said system A system is superior to the other if:
A cost is lower than B, and the benefits of both
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 corporation System
Break Even point Analysis
Payback Period
Discounted payback period
Internal Rate of Return
SELECTING THE PROPER SYSTEM
Cost categories
Hardware
Software
People
Suppliers
Telecommunications
Physical sites
Cost details
Comparing the cost of information systems through the life of the system, analysts projection how cost changes for the future and there are 3 models cost information system, namely Linear, and exponentially Step Function
SELECTING THE PROPER SYSTEM
Cost information system can occur only once and can also occur on an ongoing basis.
Information system costs that occur once only cost that is on time and development costs that occur during the development of the system.
Cost information systems that occur on a continual basis are recurring 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
Reducing the time to fix errors
Reduce the response time from the workstation alternative
Accelerate the provision of the information
Improve security systems
Propagate update records on the source
Increasing user satisfaction
FACTORS INTO CORPORATE STRATEGY
Customer satisfaction
Sales increased
Consumer and the vendor's commitment
Information marketing products
Presenting learning SYSTEM
Make short presentations
Reduce the explanation of technical detail
presentation clearly 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 information that there are alternative suitable conditions experienced by the company.
Continuing KEPUTUSAN OR NOT
if the company decided to develop the information system, the department will do the next process, namely Design System.
If then the System Development Life Cycle (SDLC) will be terminated.
Will be often found problems with the system and the study and top management will usually ask for the fulfillment of the re-study system.
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 phase or SDLC is not Go - No-Go Decision.

References
1. Martin, Merle P., Analysis and Design of Business Information Sytems,
Macmillan Publishing Company, New York, 1991.

Information system development

2009-03-07T20:01:00.012+07:00

Developing an information system means arrange a new system to continue as a replacement an old system.
The importance of developing an information system is:
1. problems
Main factor which caused the old system was replaced with the new system because of problems with the old system.
· Irregularity:
Irregularity in the system can cause the old system does not function in accordance with expectations.
For example:
System of a warehousing company, the note has some bugs so that employees can do, such as cheating, cheating to manipulate the data the company's fault or error that is not intentional. Of course this may because the truth of the data is not guaranteed. Therefore, the work of the system will not operate efficiently in

· Growth Organization:
Growth may cause the organization must arrange the new system. The growth of this organization are the information needs of the more knowledgeable, the volume of data increases, the change in the principles of organization and others, causing the old system does not operate effectively.
For example:
a banking company, the company is first to use a SQL database, but the longer the more the customer so that the volume of data to be increase. This requires that the company is changing the banking system into the information-based oracle that can accommodate the new customer data.

2. Opportunity

Information technology is now developing very rapidly. In the current era of competition such as this, information is needed in support of a decision. So companies need a system that can process the information appropriately in accordance with the development of the era.
For example:
Restaurant attract customers by providing hotspot service free to customers who lunch or dinner at the. So that visitors can browse while eating or they can use restaurant to conduct business meetings or other activities.

3. instruction

Change a system can occur because of intruction superiors or the environment outside.
For example:
customers bank who complain to the queue system were established at the time of the transaction. Because of the wide costumer cause a long queue so that many customers tired of standing. Complaints from customers is the bank should change the old system into the new system is using the automated system.

The purpose or goal of developing an information system
There are 3 goals in the development of a system that is:

· Solve the problems that are mainly caused by the old system.
· Seize opportunities in the era of competition, such as now. So companies need to utilize information technology in order to survive and develop.
· Fulfill the instructions given in both in and outside the company environment.

The Organization expectations after implementing the system organization

Performance
performance improvements so that the new system is more effective. Performance can be measured from the throughput and respon time. Throughput means the amount of work that can be done at a certain time. Response time is the average time the pending transaction between the two plus the response time to respond to the job.
For example:
a supermarket to replace the system that excels in sales into the system cashier. So the system is expected cashier will be able to calculate quickly and accurately in accordance with the information required by cashier and customers.

Information
Improving the quality of information generated by the system
for example:
accounting information system that can provide benefits such as company reports and monthly employee salaries, etc. that cannot be done by the old system.

Economy
the new system is expected to increase the benefits or advantages to the company so that it also expected a decline to the cost of going
for example:
a warehouse in a company still using manual system checks in the goods entrance or exit of goods. So that requires a lot of employees on duty, but for now check warehousing system change in the use of information technology systems that can work automatically. So that they can save the labor and production costs can be derived.

Control
Detect and fix errors
for example:
at the supermarket, supermarkets now have been using bar code system for checking and selling goods. So by using this system will be able to detect errors at the time of the transaction with the customer.

Efficiency
Operational efficiency related to how resources are used with the minimum of waste.

Services
Improvement of the services provided by the system.
For example:
the banking system that is able to give even a report that is required in accordance with user preferences

the principles of developing an information system

1.system for management
system is developed for management purposes so that the system must be able to support the needs required by the management

2.system is a large capital investment
information system is identical with the use of technology so that require a large capital to develop it. So every investment capital should consider 2 things, namely:
· All alternatives should be investigated in order to minimize the opportunity cost. Several alternatives should be in the investigation to determine the most profitable alternative.
· Must be the best investment value
said the new investment if the value has. That is the benefit or result great than cost to obtain it from. Cost benefit analysis or cost analysis Effectiveness can be used to determine whether the project is worth investigation or not

3.system developed that require people educated
does not mean the system should be the people who educated about the system but can also be done by providing on the job training to users on how to use the system that is applied.

4. Worked phase to be done in the process of system development
system development cycle generally shows stages work tasks or work to be done. Some development methodology system also provides a more detailed concept work to be done in the process of developing the system.

5. Process development system does not need Ascending
For example:
in the development of the system, the design output is the phase that must be done before the design file. However, this does not mean all of the output should be designed all new design file, but can also be done simultaneously with.

6. Don’t afraid to cancel the project
Cancel the project that are not practical anymore, re-evaluate, adjust the cost and time will be increased, reduce the scope if the cost is not enough to pay for system. After that is expected to manage the risk, to control what may fail later in the project before the process of risk arising

7.documentation there must be guidelines for the development system
documentation created and collected during the process of development of the system can be used for communication between the analyst and the system can be used to encourage the involvement of the system.

The principles of developing an information system
1. Waterfall model

This method proposes an approach to software development and systematic sequential.
Consists of the planning stages of the system (system engineering), analyzes needs, design, writing programs, testing and maintenance the system.
· Requirement or planning systems (systems engineering),
at this stage needs done on the system level, namely the needs of the hardware, software, and databases. Needs of this important collection is done because Software information system that will be built is part of the computer system.
· Analysis of information system needs, at this stage needs to be done collection information system software in the form of input data, processes that occur and the expected output with the interviews and observations, the results from the diagram can be a data flow diagram (DFD) with a data dictionary, relation entity diagram (ERD) or change in the status diagram (STD).
· Design, at this stage to translate the needs analysis in the form of a draft before writing the program in the form of the design of the interface (input and output), the design files or databases and the design procedure (algorithm).
· Implementation, the results on the design changed to the form understood by machines in the form of a programming language. If the detailed design of the program can be done quickly.
Testing, testing process focuses on:
internal logic device to ensure that all statements in the test and has been on an external drive that is functional testing to find errors and to ensure that the limited input that will give the actual value.
· Maintenance
is a system of care that can be used continuously.

The weakness of the waterfall model:
· Iterations often cause new problem
· Client difficulty for all states to explicitly want beginning stage of development.
· The new software will be developed long after the project development starts

Model prototipe (prototyping model)

starting with the collection needs and improvements, the design quickly, forming
prototype, prototype evaluation of the customer, improvement prototype and final product.

· Reaction of the user, beginning with a show prototype information system, and then see the reaction from users when working with the prototype if the features in the system prototype is already in accordance with their needs. Reaction is collected in the observation, interviews and the questionnaire.

· User suggestions, advice is the result of the interaction user with the prototype is shown (user evaluation) which is the input for the improvement, conversion or
'Stop' so that the prototype can meet the needs users better.

· Innovation is the ability of the new system previously did not have at the time the user interacts with the prototype. Innovation prototype if successful will become part of system so results.

· Plan revision, describes the prototype system in the future.
Plan to help identify revision priorities what will be next prototype.

3. Spiral model

This method of analysis of the risk. If the analysis shows there is a risk of uncertainty of demand, the development system can be stopped.
This model is divided into 6 activities are:
1. Communications customer, comunication between developers with customers to determine needs work.
2. Planning, defining the resources, the time-relation information and other projects.
3. Risk analysis, to determine the technical and risk management.
4. Engineering, to build one or more applications that can be represented.
5. Construction and launch, to mengkonstruksi, test, install and provide user support (training).
6. Customer evaluation, to obtain customer feedback based on the assessment of the results of engineering.

Approaches of developing a system

1. Be seen from methodology used

The classical approach versus structured approach

The classical approach
The approach is called classical or traditional approach with the approach is the approach conventional in the development of systems that follow the stages in the life cycle without system provided with the tools and techniques are adequate.
Problems:
· software development will be difficult
· cost of care and maintenance will become more expensive
· possibility on the size of the error system
· success of the system less secure
· problems in the implementation of the system

Structured approach
is an approach to the development of the new system is equipped with several tools and techniques so that the result was successful. Through this approach, complex problem in the organization can be solved and the results from the system will be easy to maintain, flexible, more satisfied users, have a good documentation, on time, according to the budget cost of development, can improve productivity and quality will be better .

2. Be seen from the target to be achieved

the piece approach versus system approach
the piece approach
Emphasizing that the application or on an activity without considering the overall objectives of the organization.
System Approach
emphasizing that the approach in achieving the overall goals and see the system as a whole is unity.

3.Be seen from how to determine the needs of the system

the bottom-up approach versus the top-down
Ride-down approach (bottom-up)
The Approach that starts from the bottom level of the operational level where the transaction is done. Is a discrete approach to classical . Known by the term data-analysis because the pressure is to be data to be processed first, the information generated subsequent to the data.

Top-down approach (top-down)
Starting from the approach that the top-level strategy planning . Is a discrete approach to structured . Also known with the decision-analysis because the pressure is to be the information necessary for decision making by management and the data processed is defined overtake the information required.

4.be seen of how development
The system-comprehensive approach versus modular approach

Comprehensive approach
Develop a system simultaneously and comprehensively
Is a discrete approach to classical

Modular approach
Split the system into the complex parts of a simple
System to be developed on time, easy to understand and kept
Is a discrete approach to structured

5. seen from the technology used
The far-jump approach versus developing approach

The far-jump (great-loop approach)
Develop a system simultaneously using the advanced technology
High-risk and spend a lot of cost
Developing approaches (evolutionary approach)
Applying advanced technology for application-specific applications
Developed for the needs
Cost effective and can follow the development of technology

the meaning of methodology, method and algorithm

System development methodology is the methods, procedures, concepts of work, the rules that will be used as a guide how and what should be done during this development. While the method is a way / technique systematically to grind. Continuity procedures for the settlement of this issue are known by the term algorithm. System development methodology that will be used in this case is a structured approach. Structured approach to introduce the use of tools and techniques to develop a structured system.

three classifications of development methodology

1. Data-oriented
Emphasizes the characteristics of the data processed
Data-flow oriented: modules according to the type of data elements
Data-oriented structure: the structure of input and output
2. Prescriptive
Usually provided by the manufacturer of the software
3. Functional decomposition
Emphasize breaking system subsystem
Example: HIPO, Stepwise refinement, iterative stepwise refinement, information hiding

Tools for developing a system
Shaped graph: HIPO, SADT, Jackson's diagram, and other
· Tools that use the chart:
Charting activity: describes the activities, for example: Gant chart, flowchart, etc.
· Layout charting: describes the layout
· Charting a personal relationship: describes the relationship of personnel, for example: organization charts, work distribution chart

techniques used in developing a system
1. Project management techniques used to project schedule
for example: CPM (Critical Path Method) and pert (Program Evaluation and review technique)
2. Fact-finding techniques
the techniques that can be used to collect data and find the facts in activities to learn the system that exists.
Techniques that can be done are:
· Interview
· Observation
· Questionnaires
· Sampling
3. Technique to analysis of cost / benefit → cost-benefit and cost-Effectiveness analysis
4. Technique to run a meeting
5. Technique to inspection

The differences of being a system Analyst and a programmer
Analyst system: study of the problems and determine the needs of the system to identify solutions
Programmers: write a program code based on the building design is created by the analyst
System analyst duty bridge the knowledge gap that occurs between the user and system programmers

Responsibility of the programmer than the system analyst
Programmers
1. Responsible limited to the programmer of making the computer
2. Knowledge programmers just limited to computer technology, information systems, utilities and languages program is needed
3. Jobs of Programmers are technical and must be precise in making the program instructions
4. Jobs Programmers don’t have relationship with the people, limited to a fellow programmer and systems analysis to prepare a design program.

Analysis system
1. Responsible analyst system not only on making a computer program, but the system overall
2. Knowledge analyst systems must be knowledgeable, not only in computer technology, but also in the field of application in
3. Job of systems analyst in making the program limited to solving the outline.
4. Job of systems analyst relations system involving many people, not limited to fellow analyst system, but also the programmers and system managers

The knowledge a system analyst should posses
Technology, data processing, computer programming and
Business knowledge in general
quantitative methods: regression, linier programming
Problem-solving skills
Communication skills among the personnel
Expertise builds relationships between the personnel

library:
1. analisis dan desain sistem informasi (jogiyanto)
2.rekayasa perangkat lunak (Roger s Pressman)

Information System Analysis and Design

2009-02-20T19:27:00.000+07:00

The approach of base concept of system

There are two approaches to define the system itself.

1. Procedure Approach

System is a work of network from procedures which is having a mutual connection and together to do the activity or to finish a certain target. (Taken from fundamental of system analysis).
Definition of procedure is the correct sequence from a number instruction which is to explain what must doing, who is done it, when it done and how we done it.

2. Element Approach

System is interacted a group of elements to achieve a certain goal.

Both of definition about system above is right because the definition of system is important role for studying about system definition approach. The approach of system is a group of elements or components or subsystem is a general definition of system itself.

For example:

The company information system is consisting of several subsystems there are inventory subsystem, accounting subsystem, marketing subsystem and etc.

The purpose of system

System has a certain purpose there is:

The purpose of system is to achieve a goal.
For Example: for business system, goals are correctly of purpose for the system.

The purpose of system is to achieve an objection.
For Example: the accounting system and other subsystem from business system, an objection is correctly of purpose for the system.

The characteristic of the system

- Components of system
An integrated a set of components for collecting, storing and communicating information.

- Boundary of system
Boundary of system is scope area between another system and environment.

- Environment
Environment means is everything outside the system boundary.

- Interface
Link between subsystems to another subsystem

- input
Input means all of resources that entered into the system

- output
Output means result of input have been processed.

- Processing
A process from input to be output

- Goal
It’s functioning because there are limits to what it can do and how it can achieve its purpose within its environment

The Classification of system

The Classification of system from several viewpoints such as:

1. Classification of system as abstract system and physical system
2. Classification of system as natural system and human made system
3. Classification of system as deterministic system and probabilistic system
4. Classification of system as close system and open system

Base concept of information

The information is useful for system itself to avoid entropy processing or negative entropy (negentropy). The Information as a concept has a diversity of meanings, from everyday usage to technical settings. Resources of information are data. Data refer to a collection of facts usually collected as the result of experience, observation or experiment, or processes within a computer system, or a set of premises. Data are often viewed as a lowest level of abstraction from which information and knowledge are derived.
Example of information is marketing report from salesmen is useful for management to determine the bonus.

Quality of information

The quality of information

- Accurate is measured by comparing the data to actual events .Payroll information must be exact or accurate. For example the information must be simple, not confusing and true free from mistakes.

- Timeliness
The information likes real time system. Its means that the information comes to user can not be late.

- Relevance
It means the information must have advantages and useful for users.
Information is relevant if it leads to improved decision making. It might also be relevant if it reaffirms a previous decision.

Value of information is depending on 2 factor, advantages and cost.
An information has a high value if the advantages more effective than the cost to get it

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2009-02-18T13:27:00.000+07:00

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