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How do you use an ALT in a sequence diagram?
alt is used to describe alternative scenarios of a workflow. Only one of the options will be executed. opt is used to describe optional step in workflow. For example, for online shop purchase sequence diagram you may use opt to describe how user can add gift wrapping if she wishes.
What is ALT in sequence diagram?
An alternative combined fragment is used to specify an area of a group of lifelines/ actors to show conditional flow in a sequence diagram. It also models the if-then-else logic in the sequence diagram.
How do you represent a database in sequence diagram?
As you know, there is no fixed way to represent database. One possible way is just simply creating a Lifeline with with “<>” or “<
How do you break in a sequence diagram?
Breaks are most commonly used to model exception handling. This sequence diagram example uses a break combination fragment because it treats the balance < amount condition as an exception instead of as an alternative flow. To read this example, we start at the top left corner of the sequence and read down.
How do you make a simple sequence diagram?
Just navigate to the UML Sequence shape library, and click “Use Markup.” A text pad will open, where you can type out the order of your sequence and its rules. When you’re ready, click “Build” and click back out into the editor to see your new automatically generated sequence diagram.
How are messages represented in a sequence diagram?
Sequence Diagram Notations. A sequence diagram is structured in such a way that it represents a timeline which begins at the top and descends gradually to mark the sequence of interactions. Each object has a column and the messages exchanged between them are represented by arrows.
When does an interaction occur in a sequence diagram?
In a sequence diagram, an interaction between two objects occurs when one object sends a message to another.
When do you use a rectangle in a sequence diagram?
It is used to indicate that an object is active (or instantiated) during an interaction between two objects. The length of the rectangle indicates the duration of the objects staying active. In a sequence diagram, an interaction between two objects occurs when one object sends a message to another.
How to specify the reference fragment in a sequence diagram?
To specify the reference fragment, you have to mention ‘ref’ in the name box of the frame and the name of the sequence diagram that is being referred to inside the frame. For more sequence fragments refer to Beyond the Basics of Sequence Diagrams: Part 1, Part 2 and Part 3.