A class diagram describes the structure of a system by showing the system's classes, their attributes, operations (or methods), and the relationships among the classes.

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UML class diagram notations: Differences between Association, Aggregation and Composition

I'm confused about some of the notations of UML class diagrams. Pretty sure I know what Association means. Any relationship between instances of two classes, where an instance of one class needs to ...
6
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2answers
21k views

What does the arrow mean in a Class Diagram?

I need help trying to understand what the meaning of the arrow in a UML Class Diagram is, more specifically in this Composite Diagram. What's the difference between the simple line (from a class to ...
6
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1answer
479 views

How to display in compositional relationship that the item knows about the container?

I'm drawing a class diagram and noticed that sometimes I got a relationship (composition or aggregation) where the item uses the container, and sometimes not. What is the visual difference in a ...
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How to Model a simple file-system by UML class diagram

I want to model a file system which contains both files and directories, and directories can contain either files or other directories. This is what I have reached so far: In OOSE book, however, a ...
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3answers
6k views

How do you annotate instantiation in UML class diagrams?

Given this pseudo code: class B { } class A : B { int val; }; alpha = new A(); What arrow do I draw between alpha and A in a UML class diagram? Is this even something UML is meant to do? ...
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Java code generation from class diagram

I'm on the way developing a Java application where user can provide a class diagram and get the corresponding Java code. I don't know how can I let the user interactively draw a class diagram in ...
4
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1answer
145 views

How to correctly draw a UML class diagram with fully qualified association?

Given the following code I have to draw the corresponding class diagram: public class Shop { List<Client> clients; Storage store; User chief; Set<Invoice> invoices; } ...
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3answers
879 views

How bad is it to have two methods with the same name but different signatures in two classes?

I have a design problem related to a public interface, the names of methods, and the understanding of my API and code. I have two classes like this: class A: ... function collision(self): ...
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5answers
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What classes to put exactly in a class diagram?

What classes must I put in a class diagram? Only classes used in Business Layer and associations between them? Or also other classes in the Data Access Layer, Service Layer, etc.?
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1answer
196 views

How to draw a class diagram where a class contains either 6 other classes or mupltie different

I know the basics but do not how to model this (it is an exercise with no solution provided): An order can contain 1 or more cartons of beer. Each carton contains 6 beers of the same kind but ...
2
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3answers
1k views

Should we include external systems in Class diagram?

I want to draw a class diagram that shows the following for an application: An external content management system that publishes some news items. The class that represents the news item in my ...
2
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3answers
361 views

How do I show 'creates' in a UML class diagram?

Let's say my code is going to look like this: public class MyController { private Foo foo; private FooGenerator fooGen; //setters public void work() { this.foo = ...
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1answer
1k views

UML representation of specific factory pattern

I have to create an UML class diagram from the following example code (Perl). I don't think that the standard factory pattern match in my case or I don't understand it correctly. I don't have ...
2
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1answer
3k views

What is the difference between UML Data profile and ER model?

I have been asked this question and even after a lot of research, I cannot find the answer. When I design a database using Entity relationship (ER) and then re-draw it as UML class model (extended ...
2
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2answers
268 views

How can I indicate if an object operates with another one in an UML class diagram?

Suppose I want to draw a class diagram of a DAO and an Entity. The DAO is used to load instances of the Entity from the database. How can I represent this relationship on my class diagram? Is this ...
2
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3answers
1k views

What to use in UML for included module in ruby?

I like to create simple class diagrams for my projects. Most of the time I just use composition, inheritence and associations. IMB's basic UML resource tells all about this. However I'm using ruby so ...
2
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2answers
826 views

Package diagram for an MVC patterned project?

We are required to make a package diagram for our senior project. Since our project uses MVC patter design, we created an MVC class diagram, now, our problem is in creating the package diagrams from ...
2
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1answer
67 views

Class diagrams and frames

UML class diagrams (1st pic) and frames (which belong to knowledge representation and artificial intelligence) (2nd pic) look pretty alike. But do class diagrams exactly type of frames or they just ...
2
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1answer
247 views

UML diagram for an existing implementation

I have some code, which I want to present in UML, but I've stuck at one point. Let me tell you something about code's functionality. I have a workspace in which I can place some Components, select ...
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3answers
32 views

How to represent the following scenario in a class diagram?

Consider a store with multiple branches and a system generates reports for each branch monthly and annually and an overall report as well monthly and annually. So in total there are 4 types of ...
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4answers
4k views

best way to handle a many to many relationship?

I am drawing a class diagram and I want to know what's the proper notation for many to many relationship between supplier and product? Should I show the table created supplier_product or leave it out ...
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1answer
181 views

Why do you reduce multiple inheritance to the diamond problem?

Whenever I read something like this: Many programmers exhibit a slight, involuntary shudder whenever multiple inheritance is mentioned. Ask them to identify the source of their unease and they ...
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3answers
291 views

UML Class Diagram: How can I represent “orthogonal” generalizations (or multi-inheritence)?

I try to represent in a UML Class Diagram the following object and features: The Object: A System (e.g. an electronic device) that can be of Type A, B or C If the System is of type A, it has a ...
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1answer
284 views

Should dependency relationships always be shown on class diagrams

I recently started using the Object aid UML generator plugin for Eclipse and noticed that by default adding of dependency relationships is switched off. This made me wonder if in most cases they ...
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1answer
129 views

Inheritance vs Class Diagram [closed]

What is the difference between an inheritance diagram and a class diagram in UML? For the Computer Science A Level (a British test administrated by Cambridge University, so it's possible that this ...
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2answers
826 views

How show Attributes which appear In Many To Many association

As we know a many to many association are shown by two asterisks in both end of association. Now I have a association between two entities "Good" and "Invoice" so Good and Invoice have a many to many ...
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1answer
39 views

Visibility notation in UML class diagrams

I'm reading about UML class diagrams and notation for visibility, and I can't tell if this book (Learning UML 2.0 by Russ Miles) has a typo or is just not explaining itself. Consider these two ...
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1answer
202 views

UML diagram for attributes that can have two different types

I have been to an interview for a financial programming job, and I could not answer to one question for sure. I thought about it again, but I really cannot find a good answer. They asked me to design ...
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1answer
511 views

How to represent a multiple choice attribute in UML class diagram?

I'm modelling a Filter class that stores the options for filtering a search. Some of the attributes are multiple choice. For example, if you are filtering hotel rooms you have a Price attribute that ...
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2answers
320 views

Confusion about associations in UML class diagram

--------------------- ---------------------- | FLIGHT | | STEWARD | --------------------- ---------------------- | Arrival time | | Steward ID | | ...
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1answer
172 views

How to manage coupling in model classes

I'm doing a class diagram for a game project, but I'm stuck on a coupling problem. Context The projet is a turn-based game. Two users are playing. They've got units on a map. They play until 1 ...
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3answers
245 views

What alternative is better to diagram this scenario?

I was creating and discussing a class diagram with a partner of mine. To simplify things, I've modify the real domain we're working on and made up the following diagram: Basically, a company works ...
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1answer
124 views

How to show link between a java class which gets JSON data from PHP script

I am trying to show the relationship that a java class has with a PHP script. The PHP script gets data from a database and then converts it into JSON format. This is then read by the java file. In my ...
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1answer
125 views

Finding methods of classes from the use case

I know some nouns in the use case scenario are candidate to be class, for example member, customer, student .... I can find such entities and some attributes of them, but my problem is that I can't ...
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1answer
526 views

UML class diagram - can aggregated object be part of two aggregated classes?

Some sources say that aggregation means that the class owns the object and shares reference. Lets assume an example where a company class holds a list of cars but departments of that company has list ...
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1answer
2k views

UML Class diagram confusion

I am learning how to draw a UML class diagram and after reading a few tutorials, I am still confused about the appropriate usages of Association type (The clear diamond and black diamond). I ...
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1answer
480 views

How would you go about creating a class diagram for a JPA/JSF application

I was creating a class diagram for an application I was working on today and I didnt include the JPA entities since I had all the information I thought was important in my DAOs, for example, I just ...
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2answers
190 views

Can a UML class diagram show two different relationships between two classes?

I have a class which has an inner (nested) class. I have shown this relationship between the two classes in my class diagram. However, I am also using the inner class within the outer class... do I ...
0
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4answers
569 views

Does it make sense to generate java classes from class diagram?

As we do design & analysis before development, wouldn't be convenient to be able to generate Java classes from a class diagram? This would promote more exhaustive design and better codes, right? ...
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2answers
361 views

How to indicate that a class might implement an interface?

Say I have a class User and an interface Administrator. Some users are administrator and can thus implement the interface. Most aren't, however, so it's false to say that "User implements ...
0
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1answer
533 views

I want to draw class diagram, but I don't know how to put server and database inside? [closed]

I just started to draw class diagram, I think it is based on 3-tie architecture. I have mobile application, servers, database, and web interface. But I do not know if it should put the server in? I ...
0
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2answers
190 views

Subclassing to avoid line length

The standard line length of code is 80 characters per line. This is accepted and followed by the most of programmers. I working on a state machine of a character and is necessary for me follow this ...
0
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3answers
884 views

UML - Class Diagrams Order -> Products

I have a class diagram that is like this: < Order > (1) CAN HAVE (M) < products > But therefore Order has the following: Order_Id Customer_Id Order_date_day Order_date_month ...
0
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1answer
73 views

What is the UML idiom for classes that are too big to fit into one box? [duplicate]

I am documenting an existing system using UML 2, and a few of the classes are too big to comfortably fit into a single class box. So far, I've resorted to breaking up the class into multiple boxes ...
0
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3answers
98 views

Should foreign keys be represented directly when mapping database tables to classes? [closed]

Ok, in my database I have a table Event and a table Room. Each Room can have many Event. Room table roomID-roomName 1 - cafe102 ... Event table eventID- Time -type -roomID 1 - 11:20 - 1 ...
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2answers
172 views

What kind of design diagram is this?

Here is a kata for the Bowling Game problem. Slide 9 (below) shows a design diagram. But its not obvious to me which box is a class and which is a property or method from the makeup of the boxes ...
0
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1answer
178 views

How can attributes/annotations be illustrated on a UML class diagram?

Many programming languages offer a way to annotate types. For instance, in .NET this can be achieved by deriving a custom attribute class from System.Attribute and then annotating another type with ...
0
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1answer
514 views

My UML class diagram is too complicated, what should I do?

Classes have 10-20 links with one another and you can't see anything in that mess of a diagram Unfortunately we finished coding already and if we change the class diagram we have to redo the whole ...
0
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1answer
2k views

Class Design and Structure Online Web Store

I hope I have asked this in the right forum. Basically, we're designing an Online Store and I am designing the class structure for ordering a product and want some clarification on what I have so ...
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1answer
245 views

Multiplicities and ternary relations in UML and ER

With entity–relationship diagrams, there are two conventions of denoting multiplicities, (I) and (II): Say, a teacher T is giving ‹G› some lectures L. Then we can either write this as 1 ...