Help deciding on Use Case Diagram parts

I am finding it confusing about how detailed each oval/elliptical element should be in a Use Case diagram. I feel like i should be making each process i see as an oval, but then when i look at examples, they don't always do that, and instead detail them in the flow description. I can't understand how to separate this.

For example, here is my requirement to map out:

• A user should be able to create and assign a Note to himself or another user, depending on security privileges.
• The search can search by description and subject and then display only those Notes that match.
• The ability to add a开发者_运维问答ttachments to a note is needed.

Personally i created only 2 ovals (). They are (Create Note) and (Search Note).

1. Should i also have an oval for (add attachment to note), or is that only described in the flow description.

2. Should i detail in the ovals that the user can search by description and subject, or is that again, described in the flow.

I guess you can see that i'm confused at how much detail i should make the Use Case diagram. I can't quite separate at what level it should be.

Please help. Thanks

Well,

As a rule keep your use case diagram simple. It should give generall overview of what a user can do with your system under design. Details are captured by written Use Cases: text stories, widely used to discover and record requirements. Actually, written use cases are more important than use case diagrams.

How much details should be in your use case diagram? Not much...The real question is how much details should be in Use Case Description? (written use cases)....I have no "cooked ready for eat" answer for this. But there is nice article by Kevin Bittner : Managing use-case detail Check this link

By the way, do not investigate too much time with Use Case Diagrams. Focus on real use cases(written ones) not the oval shape one.