MIS lecture 8
Terms
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- Design
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process of describing, organizing, and structuring the components of a sytem at both the architectural level and at a detailed level
- converts functional models from analysis into models that represent the solution
- technical issue-focesed
- requires less user invovlement than analysis - Automation system boundary
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- partitions data flow processes into manual and automated systems
- processes and data flows can be inside or outside boundary - System Flowchart
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representation of various computer programs, files, databases, and associated manual processes
graphically describes organization of subsystems
can show type of system (batch, realtime) - batch processing
- a method of collecting and processing data in which transactions are accumulated and stored until a specified time when it is convenient or necessary to process them as a group
- Structure Chart
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describes functions and subfunctions of each part of system
shows relationships between modules of a computer program
simple and direct method
- each module performs a specific function
- each layer in a program performs specific activities - Module
- a logical unit of a program that performs one or several functions
- structure chart basics
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-there is a single coordinating module at the root
-modules below the root are called by the coordinating module
-each module is represented as a rectangle containing a descriptive name of its function - Transaction analysis
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- system flow chart and event table inputs
- upper-level modules developed first
- identifies each transaction supported by program - Transform analysis
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- computer program transforms inputs into outputs
- structure charts have input, caluculate, and output subtrees
- uses DFD fragments for inputs - Steps to Create a Structure Chart from a DFD fragment
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- determine primary information flow
- find process that represents most fundamental change from input to output
- redraw DFD with inputs to the left and outputs to the right
- generate first draft of structure chart
- add other models (input, data storage, output0
- add logic from structured english or decision tables
- make final refinements - Module coupling
- measure of how module is connected to other modules in program
- Module cohesion
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measure of internal strength of module
module performs one defined task - what kind of modules are desirable? (in regards to cohesion and coupling)
- highly cohesie and loosely coupled modules are desirable
- Module Algorithm Design: pseudocode
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- describes internal logic of software modules
- variation of structure Enlish that is closer to programming clode
- syntax should mirror development language