A use case is a part of a job that leads to an observable result. The person who performs each use case is a system or user.
Each use case describes the behavior. The use case is formed from a template and a natural language description. The description may be represented as a flow chart.
The user performs the operation via an interface. The effects of a use case is called post-conditions. The state required for a use case is executed is called pre-condition. The units are contextual data upon which the use case works.
An object model is a particular realization of a model class. Its task is to show to illustrate the models. And 'possible to insert attributes, name and methods within a class model. The interpretation of the classes depends on the context.
In the moment in which define the relationship is necessary to assign to each report on the cardinality and a name (with an arrow), so as to read correctly the report.
There are three types of reports:
-Inheritance means that an object has different characteristics, but they can be represented with the same subject.
-Composition, indicates that some objects are part of other objects. And 'represented by a diamond on the side of the container. The cancellation of a composite object, requires the deletion of all components.
Cardinality and conditions
The cardinality may be:
-0 ... 1 (zero or one).
-1 (Only one).
-0 .. *, * (Zero or more). Quesya cardinality is the default.
-1 ... *, + (One or more).
-N (only n).
-0 ... N (from zero to n).
N-m ... (from m to n).
OCL (Object Constraint Language)
OCL is part of the UML. It is a language used to express conditions of an information system based on objects. What you can do is CRUD (create, read, update and delete) and are made of entities. And 'possible to define associations through extensions.