DATA FLOW DIAGRAM
Data Flow Diagram (DFD) is a tool that is used to describe a system that already exists or the new system will be developed logically without considering the physical environment where the data flow or the physical environment where the data is saved. DFD This is also called by the name Bubble chart, Bubble diagram, process models, work flow diagrams, or models function
Foreign entity Is unity in the environment outside the system that can be a person, organization or other system that is in the outside environment that will provide input or receive output from the systemProcess A process is an activity or work done by the person, machine or a computer from the data that flow into the process to generate data that will flow out of the process
Save data Savings is a savings of data from the data can be: a. A file or database in the computer system b. A manual record keeping or c. A box where the data in a table d. A table reference manual e. Agenda or a book
DATA FLOW Diagram Component
1. Terminator components / Foreign Entity Terminator represent external entities that communicate with system that is currently being developed. Usually known as the terminator name of foreign entities (external entity).
There are two types of terminator: Terminator Source (source): the terminator into the source. Terminator Destination (sink) is the terminator of a goal data / information system.
Terminator can be a person, group of people, organizations, departments in the organization, or company but at the same system beyond the current model is made. Terminator can also be departments, divisions or outside the system systems that communicate with the system under development
There are three important issues that must be remembered about the terminator: Terminator is a part / the environment outside the system. Flow data connecting terminator system with different processes, shows the relationship system with the outside world. Professional Systems reserve the right not to change the contents or the way work organization or procedures relating to the terminator Relations between the terminator is the one with the other not depicted on the DFD.
Process Components Describe the process components of the system that transform input into output. The process is given a name to describe the process / activities that are / will be implemented. Giving the name of the process is done with using a transitive verb (the verb need object), such as Calculating Salaries .
There are a few things to note about the process:
The process must have input and output. The process can be connected with component terminator, the data store or data flow through process.
System / sections / divisions / departments that are analyzed by professional system components are described with the
Generally, errors in the DFD process is:
Foreign entity Is unity in the environment outside the system that can be a person, organization or other system that is in the outside environment that will provide input or receive output from the systemProcess A process is an activity or work done by the person, machine or a computer from the data that flow into the process to generate data that will flow out of the process
Save data Savings is a savings of data from the data can be: a. A file or database in the computer system b. A manual record keeping or c. A box where the data in a table d. A table reference manual e. Agenda or a book
DATA FLOW Diagram Component
1. Terminator components / Foreign Entity Terminator represent external entities that communicate with system that is currently being developed. Usually known as the terminator name of foreign entities (external entity).
There are two types of terminator: Terminator Source (source): the terminator into the source. Terminator Destination (sink) is the terminator of a goal data / information system.
Terminator can be a person, group of people, organizations, departments in the organization, or company but at the same system beyond the current model is made. Terminator can also be departments, divisions or outside the system systems that communicate with the system under development
There are three important issues that must be remembered about the terminator: Terminator is a part / the environment outside the system. Flow data connecting terminator system with different processes, shows the relationship system with the outside world. Professional Systems reserve the right not to change the contents or the way work organization or procedures relating to the terminator Relations between the terminator is the one with the other not depicted on the DFD.
Process Components Describe the process components of the system that transform input into output. The process is given a name to describe the process / activities that are / will be implemented. Giving the name of the process is done with using a transitive verb (the verb need object), such as Calculating Salaries .
There are a few things to note about the process:
The process must have input and output. The process can be connected with component terminator, the data store or data flow through process.
System / sections / divisions / departments that are analyzed by professional system components are described with the
Generally, errors in the DFD process is:
1. The process does not have any input but the output. This error is called the black hole (black hole), because the data into the process and does not vanish like to include in the black hole
2. The process of producing output, but did not receive this input. Mistake called miracle (magic), because the output produced magically without ever receiving input
Component Data Store This component is used to create a model set of data packets and given the name of the plural noun, such as Student. Data store is usually associated with the storage-storage, such as file or database associated with the storage of the computer, such as a diskette file, files, hard disk, magnetic tape files. Also store data related to the storage manually, such as address books, file folders, and the agenda
A data store associated with the flow of data only on the components process, not with the other components DFD. Data flows that connect the data store with an understanding of the process have the following:
2. The process of producing output, but did not receive this input. Mistake called miracle (magic), because the output produced magically without ever receiving input
Component Data Store This component is used to create a model set of data packets and given the name of the plural noun, such as Student. Data store is usually associated with the storage-storage, such as file or database associated with the storage of the computer, such as a diskette file, files, hard disk, magnetic tape files. Also store data related to the storage manually, such as address books, file folders, and the agenda
A data store associated with the flow of data only on the components process, not with the other components DFD. Data flows that connect the data store with an understanding of the process have the following:
1.Flow data from the data store, which means as the initialization or reading one single packet of data, more than one packet of data, part of a single packet of data, or some of the more from one packet data to a process
2.Flow of data to store data as a means updated data, such as adding a new data packet or more, remove setup packet or more, or change / modify one or more data packet
In the first clear understanding that the data store does not change, if a packet of data / information from a data store to a process. Instead of the second data store has changed as a result of the flow enter the data store. In other words, the process flow of data is responsible for the changes that occur in the data store.
Component Data Flow / Data Flow A data flow / data flow is depicted with the arrow, which indicates the direction to go and out of a process. This data flow is used to explain the movement of data or packet data / information from one system to the other part.
In addition to indicating the direction, flow data on the model made by the professional system can represent bits, characters, messages, forms, real numbers, and various information related to the computer. Flow data can also represent data / information that is not associated with the computer. Flow data should be named according to the data / information is usually the name of the data flow is done by using the noun, for example, Sales Reports. There are four concepts that need to be in the drawing groove data, namely: Concept Data Package (packets of data) When two or more data flows from a source to the same goal and have the same relationship, and should be considered as a single data flow, because the data that flow together as one package
·Spread the concept of Data Flow (Data Flow Diverging) Flow of data spread shows a number of copies of data packets that originate from the same source to a different destination, or a complex data package is divided into multiple elements of data that is sent to a different destination, or flow data for a data packet that has a different value which will be sent to a different destination
·The concept of Data Flow gather (Converging Data Flow) Some of the data flows of different resources to join together towards the same goal.
·The purpose or the concept of Data Flow All data flows must contain at least one process. The purpose is this sentence:
A flow of data generated from a process and to a data store and / or terminator .A flow of data generated from a data store and / or terminator and to a process. A flow of data generated from a process and leading to a process
INVESTMENT DATA FLOW Diagram There are two forms of DFD, the Physical Data Flow Diagram, Data Flow Diagram and Logic. Physical data flow diagram more emphasis on how the process of the system applied, while the data flow logic diagram further emphasize the processes of what is there in the system. Physical Data Flow Diagram (DADF) DADF is used to more accurately describe the existing system (old system). The emphasis of DADF is how process of the system is applied (in a way what, where and by whom), including manual processes. To obtain a description of how the system is implemented, DADF must include:
2.Flow of data to store data as a means updated data, such as adding a new data packet or more, remove setup packet or more, or change / modify one or more data packet
In the first clear understanding that the data store does not change, if a packet of data / information from a data store to a process. Instead of the second data store has changed as a result of the flow enter the data store. In other words, the process flow of data is responsible for the changes that occur in the data store.
Component Data Flow / Data Flow A data flow / data flow is depicted with the arrow, which indicates the direction to go and out of a process. This data flow is used to explain the movement of data or packet data / information from one system to the other part.
In addition to indicating the direction, flow data on the model made by the professional system can represent bits, characters, messages, forms, real numbers, and various information related to the computer. Flow data can also represent data / information that is not associated with the computer. Flow data should be named according to the data / information is usually the name of the data flow is done by using the noun, for example, Sales Reports. There are four concepts that need to be in the drawing groove data, namely: Concept Data Package (packets of data) When two or more data flows from a source to the same goal and have the same relationship, and should be considered as a single data flow, because the data that flow together as one package
·Spread the concept of Data Flow (Data Flow Diverging) Flow of data spread shows a number of copies of data packets that originate from the same source to a different destination, or a complex data package is divided into multiple elements of data that is sent to a different destination, or flow data for a data packet that has a different value which will be sent to a different destination
·The concept of Data Flow gather (Converging Data Flow) Some of the data flows of different resources to join together towards the same goal.
·The purpose or the concept of Data Flow All data flows must contain at least one process. The purpose is this sentence:
A flow of data generated from a process and to a data store and / or terminator .A flow of data generated from a data store and / or terminator and to a process. A flow of data generated from a process and leading to a process
INVESTMENT DATA FLOW Diagram There are two forms of DFD, the Physical Data Flow Diagram, Data Flow Diagram and Logic. Physical data flow diagram more emphasis on how the process of the system applied, while the data flow logic diagram further emphasize the processes of what is there in the system. Physical Data Flow Diagram (DADF) DADF is used to more accurately describe the existing system (old system). The emphasis of DADF is how process of the system is applied (in a way what, where and by whom), including manual processes. To obtain a description of how the system is implemented, DADF must include:
1. Manual processes are also described.
2. The name of the data flow must include a description detailed enough to show how the systems work to understand the system.
3. Savings data can show savings of non-computer.
4. The name of saving the data type of application must indicate whether manual or computerized. Manually, for example can show notes books, desk workers. How are shows such as computerized order file, database file
5. The process must show the name of the processor, the person, department, computer system, computer program or the name of the access process.
Data Flow Diagram Logic (DADL) DADL more appropriately used to describe the system that will be proposed (new system). For computerized systems, DADL drawing only shows the process needs of the proposed system of logic, usually processes described is only the processes of a computer course.
TERMS-TERMS DEVELOPMENT DATA FLOW Diagram DFD terms of making this system will help professionals to avoid the wrong formation DFD or the DFD is incomplete or does not logically consistent. Some conditions formation DFD system can help professionals to establish the correct DFD, fun to see and easy to read by the user. Terms of making DFD are:
5. The process must show the name of the processor, the person, department, computer system, computer program or the name of the access process.
Data Flow Diagram Logic (DADL) DADL more appropriately used to describe the system that will be proposed (new system). For computerized systems, DADL drawing only shows the process needs of the proposed system of logic, usually processes described is only the processes of a computer course.
TERMS-TERMS DEVELOPMENT DATA FLOW Diagram DFD terms of making this system will help professionals to avoid the wrong formation DFD or the DFD is incomplete or does not logically consistent. Some conditions formation DFD system can help professionals to establish the correct DFD, fun to see and easy to read by the user. Terms of making DFD are:
1. Giving a name to each component DFD
2. Giving number on the component process
3. DFD representation as possible so that good views
4. Tergiversation DFD representation of complex
5. DFD is formed logically consistent
1. name for each component DFD As mentioned previously, the components represent the terminator of the environment outside the system, but have any influence on the system that is being developed. So that the user knows the system environment wherever they are related, this terminator component must be named in accordance with the external environment that affect this system. Terminator component are usually given a name with the word object.
Next is a component of the process. The components of this process represent the system functions that will be implemented or show how the system functions performed by a person, group of people or machines. So it is very clear that this component need to be given the appropriate name, so that anyone who read the DFD especially feel confident that the DFD was established that this model is accurate. Giving the name of the component process better show the rules that will be implemented by someone than by giving the name or identity of the person who will implement them. There are two reasons why not the name or identity of the person (who perform the function system) is used as the name of the process, namely:
1.people may be replaced by another person while coming, so when there is turnover every time people who carry the function, then the system must be changed again.
2.People may not perform a function of the system alone, but some of the different functions of the system. Describe the process than some of the same name but different meaning, it is better to show the tasks / functions of the actual system will be implemented
Because the component name for the process showed better task / function of the system will be implemented, the better use of the name is transitive. Giving a name for the component data store using the noun, because the data store that indicates what data is stored in the system needs to perform its tasks. If the system time when the data need to conduct its work, the data is still there, because the save system. Similarly, for the data flow component, the name given to the better use of the word. Because of this data shows the flow of data and information required and issued by the system in the implementation of its tasks
2. Tax Provision on the Process Component Usually provide a professional system with a number Ascending component in the process as a reference. It does not matter how the numbers of this process are given. The number can be given from left to right or from top to bottom, or can be also done with patterns for a specific number of these remain consistent in the number that is used
The numbers given to the process component of this process is not intended that the process is carried out sequentially. Giving this number is that a reading process in a discussion will be easier with only mention the process only if compared to the process, especially if the name is long and difficult process. Purpose of the number in the process is even more important is to show reference to the numbering scheme in the hierarchy levelisasi DFD. In other words, the number of this process is the basis of the number levelilasi DFD
DFD drawing as often as possible Depiction DFD can be done many times until the DFD technique is correct, can be received by the user, and have been professional enough so that the system rapih not ashamed to show it to the DFD and one .with other words, this depiction DFD made to form DFD is good views, and easy to read by the user and other system professionals. The beauty of drawing DFD depends on the standards required by professional organizations where the system is working and the software used by professionals in the system make DFD. delineation nice to see that can be done with attention to the following:
Size and shape the process. Some users sometimes feel confused when the size of a process different from the other process. They will think that the process with a larger size will be more important than suspected that the process is smaller. This is only the name because the process is longer than the others. So, should the process have described the size and forms of the same
Flow data and flow of data around straight. Flow data can be described with only a circle or straight line. Which is seen more comfortable depending on who will see the DFD.
DFD with the image and the image of the machine. DFD can be described manually or by using the assistance of machines, depending on the choice or professional system.
4.Giversation DFD representation of complex DFD goal is to create a model function that must be implemented by a system and the interaction between functions. Other goal is to model that made it easy to read and understand not only by the professional system to create a DFD, but also by the experienced with the subject of the case. This means that the DFD must be easy to understand, read, and fun to see
1. name for each component DFD As mentioned previously, the components represent the terminator of the environment outside the system, but have any influence on the system that is being developed. So that the user knows the system environment wherever they are related, this terminator component must be named in accordance with the external environment that affect this system. Terminator component are usually given a name with the word object.
Next is a component of the process. The components of this process represent the system functions that will be implemented or show how the system functions performed by a person, group of people or machines. So it is very clear that this component need to be given the appropriate name, so that anyone who read the DFD especially feel confident that the DFD was established that this model is accurate. Giving the name of the component process better show the rules that will be implemented by someone than by giving the name or identity of the person who will implement them. There are two reasons why not the name or identity of the person (who perform the function system) is used as the name of the process, namely:
1.people may be replaced by another person while coming, so when there is turnover every time people who carry the function, then the system must be changed again.
2.People may not perform a function of the system alone, but some of the different functions of the system. Describe the process than some of the same name but different meaning, it is better to show the tasks / functions of the actual system will be implemented
Because the component name for the process showed better task / function of the system will be implemented, the better use of the name is transitive. Giving a name for the component data store using the noun, because the data store that indicates what data is stored in the system needs to perform its tasks. If the system time when the data need to conduct its work, the data is still there, because the save system. Similarly, for the data flow component, the name given to the better use of the word. Because of this data shows the flow of data and information required and issued by the system in the implementation of its tasks
2. Tax Provision on the Process Component Usually provide a professional system with a number Ascending component in the process as a reference. It does not matter how the numbers of this process are given. The number can be given from left to right or from top to bottom, or can be also done with patterns for a specific number of these remain consistent in the number that is used
The numbers given to the process component of this process is not intended that the process is carried out sequentially. Giving this number is that a reading process in a discussion will be easier with only mention the process only if compared to the process, especially if the name is long and difficult process. Purpose of the number in the process is even more important is to show reference to the numbering scheme in the hierarchy levelisasi DFD. In other words, the number of this process is the basis of the number levelilasi DFD
DFD drawing as often as possible Depiction DFD can be done many times until the DFD technique is correct, can be received by the user, and have been professional enough so that the system rapih not ashamed to show it to the DFD and one .with other words, this depiction DFD made to form DFD is good views, and easy to read by the user and other system professionals. The beauty of drawing DFD depends on the standards required by professional organizations where the system is working and the software used by professionals in the system make DFD. delineation nice to see that can be done with attention to the following:
Size and shape the process. Some users sometimes feel confused when the size of a process different from the other process. They will think that the process with a larger size will be more important than suspected that the process is smaller. This is only the name because the process is longer than the others. So, should the process have described the size and forms of the same
Flow data and flow of data around straight. Flow data can be described with only a circle or straight line. Which is seen more comfortable depending on who will see the DFD.
DFD with the image and the image of the machine. DFD can be described manually or by using the assistance of machines, depending on the choice or professional system.
4.Giversation DFD representation of complex DFD goal is to create a model function that must be implemented by a system and the interaction between functions. Other goal is to model that made it easy to read and understand not only by the professional system to create a DFD, but also by the experienced with the subject of the case. This means that the DFD must be easy to understand, read, and fun to see
On many issues, DFD is created does not have too many processes (process a maximum of six) with the data store, data flow, and terminator that are associated with the process in one diagram. If too many processes, terminator, the data store, data flow and is described in a DFD, then the possibility exists that occurred many contradiction in the data flow in DFD. Cross flow of this data will be difficult to cause the user to read and understand the DFD certain. So the fewer the data on the cross DFD, the DFD is the better established by professional system. Contradiction flow of this data can be avoided with the DFD describes the many-level (levelisasi DFD), or by using the duplicate of the DFD components. DFD component that can use only duplicate parts store and terminator. Provision is also duplicates can not be given at a professional system that creates DFD, but little use of the duplicate, the better that DFD.
Provision of duplicate data store is done by giving straight line or symbol asterik (*), while the terminator to use a forward slash symbol (/) or asterik (*). A large number of duplicates in the duplicate symbol that is used depends on the number of duplicates is used
5. Consistent representation of DFD DFD representation of the group must be consistent another .Professional system DFD describes the DFD based on the levels of DFD with the aim that the DFD is in it easily read and understood by the system. This is in accordance with one of the goals or requirements create DFD
Drawing DFD There are no standard rules to describe the DFD. But from the various references available, outline the steps to create a DFD are:
Provision of duplicate data store is done by giving straight line or symbol asterik (*), while the terminator to use a forward slash symbol (/) or asterik (*). A large number of duplicates in the duplicate symbol that is used depends on the number of duplicates is used
5. Consistent representation of DFD DFD representation of the group must be consistent another .Professional system DFD describes the DFD based on the levels of DFD with the aim that the DFD is in it easily read and understood by the system. This is in accordance with one of the goals or requirements create DFD
Drawing DFD There are no standard rules to describe the DFD. But from the various references available, outline the steps to create a DFD are:
1. Identify the first all foreign entities are involved in the system.
2. Identification of all input and output are involved with outside entities.
3.Create a Context Diagram (context diagram)
Consist of a process and depict scope from a systemRepresenting highest level of DFD depicting all system to input and output of the systemSystem is limited by boundary (depicted by dash line)There is no storage
This chart is a chart of the highest level DFD that describes the relationship with the environment outside the system. How:
Specify the name of the system.
Consist of a process and depict scope from a systemRepresenting highest level of DFD depicting all system to input and output of the systemSystem is limited by boundary (depicted by dash line)There is no storage
This chart is a chart of the highest level DFD that describes the relationship with the environment outside the system. How:
Specify the name of the system.
> Determine the limits of the system.
> Specify the terminator are present in the system.
> Define what is received / given terminator from / to the system.
> picture context diagram
4. Create Diagram Level Zero Diagram of this decomposition is the context diagram. How:
4. Create Diagram Level Zero Diagram of this decomposition is the context diagram. How:
> 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 appear data (master) as the source and destination flow data.
> picture diagram level zero.
> Avoid snippet flow data
> Give the number on the main process (the number does not indicate the order process).
5.Create Diagram Level One Decomposition diagram is a diagram of the zero level. How: Define the process of smaller (sub-process) from the main 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 appear data (transaction) as the source and destination flow data.
5.Create Diagram Level One Decomposition diagram is a diagram of the zero level. How: Define the process of smaller (sub-process) from the main 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 appear data (transaction) as the source and destination flow data.
One picture level DFD
> Avoid snippet flow of data.
> Give the number on each sub-process show that decomposition of the process before.
Example: 1.1, 1.2, 2.1
6. DFD Level Two, Three, ...
This diagram is a decomposition of the previous level. Process decomposition is done with the process until ready to poured in the program. Rules that are used with the same level one.
There are a few things to note in drawing levelisasi DFD, namely: In the context of the diagram, there are several things that need to be system such as the relationship with the outside world that influence, representation system in a process, and data representation store (optional) which is known to store data or external data master store. Data store means this is an external data store is generated by the system that is being analyzed, but is used by another system, or store the data generated by other systems but used by the system that is being analyzed.
Balancing in the drawing need to levelitation DFD DFD Balancing this is a balance between flow of data entry / exit of a level must be the same with the flow data entry / exit to the next level
There are a few things to note in drawing levelisasi DFD, namely: In the context of the diagram, there are several things that need to be system such as the relationship with the outside world that influence, representation system in a process, and data representation store (optional) which is known to store data or external data master store. Data store means this is an external data store is generated by the system that is being analyzed, but is used by another system, or store the data generated by other systems but used by the system that is being analyzed.
Balancing in the drawing need to levelitation DFD DFD Balancing this is a balance between flow of data entry / exit of a level must be the same with the flow data entry / exit to the next level
Data Dictionary
1. Work 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 .
2. At analysis, the data dictionary is used as a means of communication between the systems analyst with the user.
3. At the system design, data dictionary is used to design input, reports and databases .
4. Flow data on the global DAD, further details can be seen in the data dictionary
Restrictions in DFD
1. Data flow not be outside of the entity directly to the other outside entities without going through a process.
2. Data flow not be directly from the data store to entities outside without going through a process.
3. The data flow not store data directly from the data store without the other through a process.
4. Data flow from one process directly to the other without going through the process of a data store should / be avoided as much as possible
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