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UML Sequence Diagram: database

 
Jesus Angeles
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How or what icon do we use to represent a database?

Lets say, an object calls a Select statement on that database? Is it a common rectangle? or an actor (stick person)?
 
Ilja Preuss
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A typical icon would be a drum - see Figure 2 at http://www.agilemodeling.com/artifacts/sequenceDiagram.htm

I don't think it's standardized, but everyone I know would recognize it.
 
Jesus Angeles
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Yes, I also use the drum in all of my Program Flow Diagrams, for the database.

However, I am strictly required to be UML compliant - UML 2.x or earlier.
 
Ilja Preuss
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UML actually allows for custom icons to be used. So, as far as I know, you would be "strictly UML compliant" even if you used an elephant as the icon for the database. Not that I'm suggesting you should do so...

As an aside, what's the reason behind being required to be "strictly UML compliant"? I'm just curious...
 
Jesus Angeles
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For SCEA part 2. (Kidding aside, Ill use tweety bird icon)
 
Frank Carver
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I think we also need to know a bit more about which of the UML diagrams you want to show this database in.

The "drum" is recognizable, but is mostly taken to indicate the database system or database hardware, and is thus most appropriate for something like a deployment or structure diagram.

When representing a database in a sequence diagram I guess it is just a regular column; in a collaboration diagram probably a regular rectangle, and so on. I can't imagine many reasons to specifically include a database in any of the other diagrams.

Can you explain what you are trying to communicate about the database and its role in the system?
 
Jesus Angeles
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On the sequence diagram, I want to connect an arrow from a DAO (EJB bmp) to the database. I think the context of my question is highly on SCEA exam, so I probably should ask this in the SCEA forum instead.

I understand that UML is quite more of a guideline, and not a strict set of rules, except when Model-Driven-Development is involved.
 
Ilja Preuss
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Originally posted by Frank Carver:

When representing a database in a sequence diagram I guess it is just a regular column;


Mhh, I like the way the drum adds to the expressiveness of the diagram in the link I've given above.
 
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