Entity Structure Diagrams (ESD)
Entity Structure Diagrams (ESDs) illustrate the time-ordered actions entities perform within the system.
An Entity Structure Diagram (ESD)
Entity Structure Diagram (ESD) Notations
Entity
An entity is an object that acts and is acted on by the system. The root of the ESD parent-child tree is a single entity (the only one on the diagram).
Learn how to edit text on entities.
Action
Actions are carried out by entities and actions affect other entities. They are linked to the root entity and each other in a parent-child hierarchy.
Learn how to edit text on entities.
Constructs - Sequence
JSD constructs are identical to SSADM Entity Life History constructs. Use a sequence construct to illustrate actions that are executed in order from left to right.
Constructs - Selection
To represent a choice between two or more mutually exclusive actions, mark the actions with a small "o" (for option) on the upper right hand corner.
Constructs - Iteration
If an action is repeated, place a small asterisk (*) in its upper right hand corner. There is usually only one action under an iteration construct.
Null Component
In an If-Else statement, a null component can illustrate a "do nothing" alternative.
