Structured Analysis Notes

Data Dictionary: Collection of names, definitions, and attributes of data elements in a database or research project.

Describes meanings, purposes, and metadata of data elements.

Ensures consistency and aids data analysis by enforcing data standards.

Lists data items in Data Flow Diagrams (DFD), including flows and contents of data stores.

Defines composite data items (e.g., $grossPay = regularPay + overtimePay$; name and type for smallest units).

Data Dictionary - Operators:

$+$: Composition ($a+b$).

$[,]$: Selection ($[a,b]$).

$()$: Optional data ($a+(b)$).

${}$: Iterative data definition (${name}5$, ${name}*$).

$=$: Equivalence ($a=b+c$).

$/* */$: Comments.

Data Dictionary - Tic Tac Toe Example:

Elements: Human Player, Display, Tic-Tac-Toe, etc.

Definitions: move, display, game, board, result.

Entity Relationship Diagram:

Shows entities (e.g., Student, Lecture) and their relationships with attributes.

Process Specification (PSpecs):

Documents decision-making logic and formulas for output data.

Reduces ambiguity, validates system design, and ensures data quality.

Process Specification Format: Includes Process Name, Number, Inputs, Outputs, and Logic.

Structure Chart:

Represents the hierarchical structure of modules.

Breaks down the entire system into the lowest functional modules.

Describes functions and sub-functions of each module in detail.

Partitions the system into black boxes (functionality known, inner details unknown).

Inputs are given to the black boxes, and appropriate outputs are generated.

Structure Chart - Symbols:

• Module: Represents the process or task of the system.

• Control Module: Branches to more than one sub module.

• Sub Module: Part (Child) of another module.

• Library Module: Reusable and invokable from any module.

• Conditional Call: Represents that control module can select any of the sub module on the basis of some condition.

• Loop: Represents the repetitive execution of module by the sub module.

• Data Flow: Represents the flow of data between the modules.

• Represented by a directed arrow with an empty circle at the end.

• Control Flow: Represents the flow of control between the modules.

• Represented by a directed arrow with a filled circle at the end.

• Physical Storage: Where all the information is to be stored