Chapter 5 - Data and Process Modeling Flashcards
Shows what a system must do, regardless of how it
will be implemented physically
logical model
A model that describes how a system will be constructed.
physical model
A physical model of the current system, a logical model of the current system, a logical model of the new system, and a physical model of the new system are all developed.
four-model approach
A popular symbol set used in DFDs. Processes, data flows, data stores, and external entities all have a unique symbol.
Gane and Sarson
A type of symbol set that is used in DFDs. Processes, data flows, data stores, and external entities each have a unique symbol in the _______ symbol set.
Yourdon
Procedure or task that users, managers, and IT staff members perform. Also, the logical rules of a system that are applied to transform data into meaningful information. In data flow diagrams, a _______ receives input data and produces output that has a different content, form, or both.
process
Rules to determine how a system handles data and produces useful information, reflecting the operational requirements of the business. Examples include adding the proper amount of sales tax to invoices, calculating customer balances and finance charges, and determining whether a customer is eligible for a volume-based discount.
business logic / business rules
A metaphor for a process or an action that produces results in a non-transparent or non-observable manner. In data flow diagrams, a process appears as a _______ where the inputs, outputs, and general function of the process are known, but the underlying details are not shown.
black box
A path for data to move from one part of the information system to another.
data flow
An unexplained generation of data or information. With respect to DFDs, processes cannot _________________ data flows—they must have an input to have an output.
Spontaneous generation
A process that has no output
Black hole
A process with an input obviously insufficient to generate the shown output.
Gray hole
A person, a place, a thing, or an event for which data is collected and maintained. For example, an online sales system may include entities named CUSTOMER, ORDER, PRODUCT, and SUPPLIER.
entity
A DFD symbol that indicates a data origin or final destination. Also called an external entity.
terminators
An external entity that supplies data to an information system.
source
An external entity that receives data from an information system.
sink
A top-level view of an information system that shows the boundaries and scope.
context diagram
In a DFD, ________ represents the entire information system but does not show the internal workings.
process 0
A diagram depicting the first level of detail below the initial context diagram. ___________ zooms in on the context diagram and shows major processes, data flows, and data stores, as well as repeating the external entities and data flows that appear in the context diagram.
Diagram 0
A data flow in which the same data travels to two or more different locations.
diverging data flow
The higher or more top-level diagram in an exploded DFD.
parent diagram
The lower-level diagram in an exploded DFD.
child diagram
A single function that is not exploded further. The logic for _______________ is documented in a data dictionary process description.
functional primitive
The process of drawing a series of increasingly detailed diagrams to reach the desired level of detail.
Leveling
A process used to maintain consistency among an entire series of diagrams, including input and output data flows, data definition, and process descriptions.
Balancing
A diagram is said to be _______ if it “drills down” to a more detailed or expanded view
exploding
The breaking down of overall objectives into subsystems and modules.
partitioning
Another way of conveying a process or system that has been broken down from a general, top-level view to more detail. The terms exploded and partitioned also can be used.
decomposing
A central storehouse of information about a system’s data.
data dictionary
A symbol used in DFDs to represent a situation in which a system must retain data because one or more processes need to use that stored data at a later time. Used interchangeably with the term data store.
data repository
A single characteristic or fact about an entity. A ____________, field, or attribute is the smallest piece of data that has meaning within an information system. For example, a Social Security number or company name could be examples of a _____________. Also called data item.
data element
A single characteristic or fact about an entity. A _____, or attribute, is the smallest piece of data that has meaning within an information system. For example, a Social Security number or company name could be examples of a ______. The terms data element, data item, and _______ are used interchangeably.
field
A meaningful combination of related data elements that are included in a data flow or retained in a data store. A framework for organizing and storing data.
data structures
A term used in various data dictionaries to indicate an alternate name, or a name other than the standard data element name, that is used to describe the same data element.
alias
The set of values permitted for a data element.
domain
Checks that are applied to data elements when data is entered to ensure that the value entered is valid. For example, _________ might require that an employee’s salary number be within the employer’s predefined range for that position.
validity rules
A documentation of a functional primitive’s details, which represents a specific set of processing steps and business logic.
process description
A design that can be broken down into logical blocks. Also known as partitioning or top-down design.
Modular design
Serve as building blocks for a process. __________ have one entry and exit point. They may be completed in sequential order, as the result of a test or condition, or repeated until a specific condition changes. Also called logical structure.
control structures
The completion of steps in sequential order, one after another.
Sequence
A control structure in modular design, it is the completion of two or more process steps based on the results of a test or condition.
Selection
The completion of a process step that is repeated until a specific condition changes.
Iteration
Refers to a process step that is repeated until a specific condition changes. For example, a process that continues to print paychecks until it reaches the end of the payroll file is looping. Also known as repetition.
looping
A subset of standard English that describes logical processes clearly and accurately.
Structured English
A technique for representing program logic in semistructured prose.
pseudocode
A table that shows a logical structure, with all possible combinations of conditions and resulting actions.
decision table
A graphical representation of the conditions, actions, and rules found in a decision table.
decision tree
