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A data structure diagram ( DSD) is the visual representation of a certain kind of data model that contains entities, their relationships, and the constraints that are placed on them. It is an older alternative to the entity–relationship model . The basic graphic notation elements of DSDs are boxes which represent entities.
A data structure known as a hash table. In computer science, a data structure is a data organization, and storage format that is usually chosen for efficient access to data. [1] [2] [3] More precisely, a data structure is a collection of data values, the relationships among them, and the functions or operations that can be applied to the data ...
Data-Flow Diagram example. A data-flow diagram (DFD) is a graphical representation of the "flow" of data through an information system. It differs from the flowchart as it shows the data flow instead of the control flow of the program. A data-flow diagram can also be used for the visualization of data processing (structured design).
The data-flow diagram is a tool that is part of structured analysis and data modeling. When using UML, the activity diagram typically takes over the role of the data-flow diagram. A special form of data-flow plan is a site-oriented data-flow plan. Data-flow diagrams can be regarded as inverted Petri nets, because places in such networks ...
With reference to the example in the above diagram: Data field label = Employee Name or EMP_NAME Data field value = Jeffrey Tan The above description is a view of data as understood by a user e.g. a person working in Human Resource Department. The above structure can be seen in the hierarchical model, which is one way to organize data in a ...
Structured analysis consists of interpreting the system concept (or real world situations) into data and control terminology represented by data flow diagrams. The flow of data and control from bubble to the data store to bubble can be difficult to track and the number of bubbles can increase. One approach is to first define events from the ...
Entity–relationship model. An entity–attribute-relationship diagram for an MMORPG using Chen's notation. An entity–relationship model (or ER model) describes interrelated things of interest in a specific domain of knowledge. A basic ER model is composed of entity types (which classify the things of interest) and specifies relationships ...
Conceptual schema. A conceptual schema or conceptual data model is a high-level description of informational needs underlying the design of a database. [citation needed] It typically includes only the main concepts and the main relationships among them. Typically this is a first-cut model, with insufficient detail to build an actual database.