external agents, processes, data stores, data flows External agent
DFD basic technique for physical DFDs 4 symbol types: external agents, processes, data stores, data flows
External agent: shows a person or organisational unit, that is outside the process being analysed, that sends data to or receives data from the process (outside the ‘system boundary’) Format: a noun or noun phrase, singular, upper case text.
BANK
Process: shows a step in a process; a person/department/organisation that transforms incoming data flows into outgoing data flows; has a unique name and number Format: noun phrase, lower case text Data store: shows a physical place where data is stored-'data at rest' has a unique name of the object that holds the data Format: a noun or noun phrase, lower case text
Data flow: shows a pipeline of information -'data in motion'; using a noun or noun phrase to describe the thing that travels; connects: an external agent to a process; a process to a process; a process to a data store; (BUT NEVER an external agent to a data store, or an external agent to another external agent!)
External agent: shows a person or organisational unit, that is outside the process being analysed, that sends data to or receives data from the process (outside the ‘system boundary’) Format: a noun or noun phrase, singular, upper case text.
BANK
Process: shows a step in a process; a person/department/organisation that transforms incoming data flows into outgoing data flows; has a unique name and number Format: noun phrase, lower case text Data store: shows a physical place where data is stored-'data at rest' has a unique name of the object that holds the data Format: a noun or noun phrase, lower case text
Data flow: shows a pipeline of information -'data in motion'; using a noun or noun phrase to describe the thing that travels; connects: an external agent to a process; a process to a process; a process to a data store; (BUT NEVER an external agent to a data store, or an external agent to another external agent!)
