Analysis Phase Flashcards
The analysis phase involves converting the ____________specification into a __________ specification.
requirements, problem
What are the three modeling techniques?
data modeling, process modeling, or object-oriented modeling
What are the major inputs and outputs of the analysis phase?
Input: Reqmts. specification
Output: Problem specification and System proposal
Along with system models and flowcharts what are 4 more of the principal tools in the Analysis phase?
Data dictionary
data flow diagrams
data models
prototyping
The components of a structured analysis include no only the context and dfd diagrams, but also what?
state diagrams, process specifications and data dictionary.
The data flows in dfds are physical and logical. T or F
F. Only logical.
External entities can represent what?
Human, subsystem or system.
In a dfd, what is a process?
Business activity/function where the manipulation and transformation of data takes place.
In a dfd, what is a data store?
storage of persistent data that is required for or produced by a process.
Rule1- Data stores must have what at least?
1 incoming data flow and 1 outgoing.
Rule2-how many incoming and outgoing data flows can one have ?
Many.
Rule3-A process can connect to which symbols?
Any, including another process.
Rule4-A data flow leaving a process is always named what?
Something different then when it came in.
Naming conventions for:
a. ) Process
b. ) Data Store
c. ) Source/Sink External entity
a. ) Verb-Adj-Verb
b. ) Noun, describing data
c. ) Noun
d. ) Descriptive noun
Rule5-When is a data store required?
When processes share data.
If output is not immediately needed by the next process, what is used and why?
A data store so that it can synchronize the process.
How does an external entity interact with the system?
By either sending the system data or receiving it.
Rule6-When is a double arrow used?
When a process is reading data and updating the data on the same table or file (i.e. data store.). A read before an update.
A context diagram contains all the external entities and what else?
The major data flows to and from them.
Diagram 0 dives into the context process (or the system itself) and should always include what?
External entities, the major processes w/in the system and major data stores.
What is a primitive process?
One without a child diagram.
A top-down approach to a dfd first includes what, then ends with what?
Listing business activities to elaborate on dfd factors (ext. entities, data flows, etc…)
Partition physical dfd to facilitate implementation.
when making a physical dfd out of the logical dfd, one must distinguish between what type of processes?
Manual and automated.
Throughout each level of the dfd, this must remain constant?
Inputs and outputs.
Rule7-If a parent diagram has a data store, can the child diagram have it too?
Yes.
Rule8-What is vertical balancing? child diagram cannot produce output or what,
A child diagram cannot produce output or receive input that the parent process does not also produce or receive. Names must also be identical.
What is an interface data flow?
Child data flows that matches parent data flows.
How is interface data flow depicted in a dfd?
With the source or destination clearly present and labeled the data flow emits from or goes to a bland area of the child diagram.
Process 5 = Diagram ___?
5
What is the rule of thumb for stopping a decomposition?
When you can explain the process in one (maybe two) sentences.
Rule9-Describe the
Unique Names” rule.
Each object on the dfd needs a unique name.
Rule10-Freestanders
Not up in here!
Rule11-2 is the loneliest number
A process must have an input and output data flow.
Rule12-Data Store Dating
Data stores must be connected to at least one process.
Rule13-External entities are assholes.
They don’t have any friends i.e. they shouldn’t be connected to one another.
Which object can only have outputs?
Source/external entity
Which object can only have inputs?
Sink/data store.
Can data move from one store to another on its own?
No! must have a process.
True or False. Data can move directly from a source to a sink.
False, data must be placed into a sink by a process.
Rule14-No playing with yourself
Data flow can’t come out of a process and immediately back in. There must be a process in between that has processed some other data flow before returning the original.
What is the operation performed by a data flow to a data store?
Update: delete, change, add
Data flow coming from a data store is what?
retrieval/use
This type of dfd includes the hardware, software, files and people involved in the system
Physical dfd
Physical dfd’s unlike logical dfds include what two things (hint: one is a dimension?
time/sequence.
Error controls.
What is a CRUD diagram/matrix?
Create, read, update, delete: shows what “processes” can CRUD to different “master file records”
What are the primary reasons for DFD partitions (i.e. areas to be included in a single program)?
User groups Execution at different times Security Redundancy Efficiency Consistency
Ex. of a data element?
Date, phone number, ssn
What is a data structure?
group of one or more related data elements and/or data structures
examples: customer_address
What is an internal data flow?
Data flow between processes.
What should be defined for a data flow?
ID, Name(descriptive), gen description, source, destination, composed of which data elements or part of which data structure.
The problem specification document will serve as the basis of the design phase, what are the components that make up this?
Current sys. deficiencies New sys deficiencies New sys restrictions Acceptance criteria System models: DFD, data, C-B Data dictionary
