Databases
StackOverflow2013
Postsdbo
PO
 

Note that there are some explanatory texts on larger screens.

plurals
  1. PO
    primarykey
    data
    text
    <p>First of all, could you please provide the source of your class diagram implementation, your inputs are not clear enough to determine the realtionships between the classes.</p> <ul> <li>(A) There are two types of arrows, the arrow with a rectangular head describes "<strong>Generalization</strong>".</li> </ul> <blockquote> <p>The specific classifier inherits part of its definition from the general classifier. The general classifier is at the arrow end of the connector. Attributes, associations, and operations are inherited by the specific classifier. Use the Inheritance tool to create a generalization between two classifiers.</p> </blockquote> <ul> <li>The second type of arrows describes "<strong>Association</strong>"</li> </ul> <blockquote> <p>A relationship between the members of two classifiers. There are two types of it, Aggregation and Composition.</p> </blockquote> <ul> <li>(B) The numbers beside arrows simply describes "<strong>Multiplicity</strong>"</li> </ul> <blockquote> <p>Multiplicity of an association end is the number of possible instances of the class associated with a single instance of the other end.</p> </blockquote> <pre><code> ┬─────────────────────────┬───────────────────────────────────────────────────────┬ │ Multiplicities | Explanation | │ | | ├─────────────────────────┼───────────────────────────────────────────────────────┼ |0..1 | zero or one instance. | ├─────────────────────────┼───────────────────────────────────────────────────────┼ |0..* or * | no limit on the number of instances (including none) | ├─────────────────────────┼───────────────────────────────────────────────────────┼ |1 | exactly one instance | ├─────────────────────────┼───────────────────────────────────────────────────────┼ |1..* | at least one instance | ├─────────────────────────┼───────────────────────────────────────────────────────┼ </code></pre> <p>You can find helpful examples in the links below.</p> <p><a href="https://stackoverflow.com/questions/1874049/uml-arrows-pointers-explanation">Explanation of the UML arrows</a></p> <p><a href="http://msdn.microsoft.com/en-us/library/dd409437%28VS.100%29.aspx" rel="nofollow noreferrer">http://msdn.microsoft.com/en-us/library/dd409437%28VS.100%29.aspx</a></p> <p><a href="http://edutechwiki.unige.ch/en/UML_class_diagram" rel="nofollow noreferrer">http://edutechwiki.unige.ch/en/UML_class_diagram</a></p>
    singulars
    1. This table or related slice is empty.
    1. POCan someone explain this UML diagram
      singulars
      1. PTQuestion
    1. PTAnswer
    1. USCommunity
    1. USMuhammadHani
    plurals
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. VO
      singulars
      1. PO
      1. This table or related slice is empty.
      1. VTUpMod
    2. VO
      singulars
      1. PO
      1. This table or related slice is empty.
      1. VTUpMod
    1. COA - Are you certain those numbers specify multiplicity? Values used for multiplicity are *, 0 and 1, while one of the numbers in the diagram is 2?! B - "please provide the source of your class diagram implementation, your inputs are not clear enough to determine the realtionships between the classes." It's taken from DDD:Tackling Complexity in The heart of software.
      singulars
      1. PO
      1. USuser437291
    2. CO@user437291 The numbers aren't restricted to zero one and many! It is saying that an `OR Specification` refers to two other specifications, in either order, presumably as it is satisfied if either of the two is satisfied. Personally I would have designed it as 2..* so you don't have to have extra `or` steps if you have a choice of more than two specifications - having a fixed number which isn't 1 is very often a design smell.
      singulars
      1. PO
      1. USPete Kirkham
 

Querying!

 
Guidance
A row detail

Detail views are divided into sections. All the information in the data section comes from columns in the selected row. The other sections display data from other, related rows.

Related data can be related in a to-one or a to-many fashion. Captions of data related in a to-many fashion link to a list view showing a filtered view of the table.

Try moving around until you find a non-empty to-many entry and click on the label to get to one. You can move back to the root by clicking on the database name in the header.

SQuiL has stopped working due to an internal error.

If you are curious you may find further information in the browser console, which is accessible through the devtools (F12).

Reload