Today I got a diagram similar to this one. The diagram I got was produced using Visio which I don't have. I haven't seen such a diagram before and its symbols are not clear to me.
I tried to google it and find some explanations about this specific type of diagram, but to no avail.
Could you please tell me what type of diagram it is, and give me some links to sites about it?
Thanks in advance.
Looks like a Unified Modeling Language (UML) diagram, in particular, an Entity Relationship diagram
Looks like Entity relationship diagram
Entity-relationship modeling is a database modeling method, used to produce a type of conceptual schema, often a relational database, and its requirements in a top-down fashion. Diagrams created by this process are called entity-relationship diagrams.
This is a cardinality diagram, and the lines represent one-to-many relationships.
http://www.smartdraw.com/resources/tutorials/cardinality-notations/
it is an ER diagram and google provides enough links
Entity-Relationship Diagram
Thanks to everyone. Using your answers and hints, I finally found out that this specific notation system of ER diagrams is called Barker Notation -- that's the answer to my own question :-)
Yes it is entity relationship diagram. As you have mentioned you don’t have Visio, you can download FREE Visio trial for 60 day. I use Visio to create IT diagrams as it has many great features.
Related
I'm stiil a newbie with Enterprise Architect. I was wondering is there a way to generate automatically a certain type of diagram from an already existing other type of diagram and if yes - between what types of diagrams it could be achieved.
For example, could a sequence diagram be generated out of a given class diagram? Or it isn't possible because the sequence diagrams are behavioral and the class diagrams are structural?
Thanks in advance!
To concrete Vladimir's answer: a diagram is not a model. If you want to transform anything you need to focus on packages (single elements would not make much sense anyway).
it is absolutely not possible transform or generate class diagram to (from) sequence because of different semantic of diagrams. It is not good idea to do any transformation between diagram definitions. If some tool allows it, it always directed to a meaningless or incomplete structures.
Please help me know as to when it(uml) is necessary. I was told that generally UML are drawn for web based application developement, for desktop based, DFDs and ERDs are used. My university requires all the diagram(uml,dfd,er). please let me know if my information is correct? Thank you
UML Diagram are imporant because it help the person to understand the relationship and dependency between different class present in the code(Class Diagram).
Flow of the program(Sequence Diagram , Activity Diagram).
Help to improve the program architecture etc.
And read about different type of UML diagram you will get more information.
Your needs in using UML depends on your position and your (self)education.
Some companies use UML. So, you would need it to get a job in them. Just now your university requires UML diagrams, so there IS a need in them, isn't it?
If you know UML a bit, you could understand the thoughts of your colleague who wants to share them with you this way.
If you understand the language of a UML diagram, you can use it for improvement of your thinking on the problem. So, you can think into the problem deeper and faster than without a tool. You should be really well acquainted with the tool though, for when inventing something new, you need to think on the domain problem, not on the language problems. But you don't need to know all the rules for this level of use yet.
If you know UML so that you can draw diagrams up to their strict rules, you have two more uses of it.
Translating your knowledge of the problem from one level of abstraction to another and modelling these levels up to the strict rules, you are filtering many misunderstandings in the already accepted model and can practically debug the model before coding. It can save much time and money.
While you are making the diagrams according to strict rules, you can collaborate on the model with your colleagues. It is always better if you can express your ideas more precisely.
As for technology limitations, you can use UML very widely, even out of the IT needs. As for IT, only GUI creation is supported badly. And anonymous classes are almost not supported in class diagrams at all (in behaviour diagrams they work OK).
DFD (datya flow diagram) and ERD (entity relationship diagram) diagram are tools for structural analysis and design, this is way to build structural application (data bases and functions). UML support quite different paradigm: object paradigm - we build application as collaborating objects. DFD and ER (ERD) diagram is not part of UML. We can use ER diagram for data base modeling and join to UML domain model by the ORM (object-relational mapping, implemented e.g. by Hibernate).
I am not sure if this is a good question as I'm unsure if there's any agreement on the subject. However due to the lack of information in the internet I'm compelled to ask anyways.
Let's say I'm making a system that is mainly object-oriented, with its corresponding UML diagrams (use-case, class, colaboration, etc). However, none of the UML diagrams are helpful when dealing with the database, which should be relevant for the developing team so they can know what exists in the database and what does not.
There are two ways to represent a database: Entity-Relationship and Relational (it's unknown to me if there are more, but those two are relevant within the relational database paradigm). ER deals with the representation of the BD in terms of business rules, and Relational deals with the actual, physical implementation. But none are "UML standard" (unless I'm missing something here).
Which modeling should I use, and why? Is ER relevant in terms of UML, or should I stick to relational? Thank you beforehand.
If you want to use UML only, you could use limited class diagrams - without m-n associations and methods. But if you are using some class-table mapping tools, you can use anything, except m-n relationships only.
Nobody had ever said that you can use Class diagram for OOP classes only. You can use them for any more or less formal concepts, if their needs can be covered by the complex of CD elements. I use class diagrams for UI planning and even formal text planning. And tables are very close to classes. So, no problem.
You can use data model diagrams, if you need something that is CALLED data diagram. But they are covered by class diagrams fully. That is the reason they are not supported anymore.
Your task is to make the model understandable for everybody, who can get it in hands. Class diagram is the most widely known UML diagram. A good title and a pair of comments will resolve all possible misunderstandings.
Both are different ER diagrams are relationship of entities and UML diagrams are behaviour of Ojects how they communicate with each other, as per my view point DFD (data flow diagram) is option. It has different levels which is based on number of processes and will better explain about data entities.
Thanks a lot for your help. I really need to make it clear :(
Yes, this is an Entity Relationship Diagram, using Chen's notation.
The inclusion of field names muddies this a bit - an ERD shouldn't really express this information AFAIK.
I think it's a UML diagram
I need some sample UML diagrams for some project of medium complexity. Do you know of anywhere where I can find some? I don't need them for learning UML, but rather to test my application that I work on and that should be able to process UML diagrams.
It would suffice to have Class diagram, Package diagram and Component diagram, but those should all model the same system and should be consistent.
Here's an Oracle paper which contains the design of a Web Store application. This paper has all kinds of UML diagrams that one may want - Class, Component, Sequence, Data Model etc. It may not have package diagrams but, those are trivial.
Look at this site, they have nice examples in the product tutorials:
Enterprise Architect
Maybe you should be more concrete about what format you need... Also, it might be interesting to try out some reverse engineering from existing code.