Attributes of a class are displayed in the second compartment of a UML class symbol. Attributes can be displayed with a visibility (see Visibility), and an initial value.

A class attribute must have a type. A type declares how the attribute must be treated. There are two basic types:.

Every language (Java, C++, Visual Basic, CORBA IDL, and so on) has a standard set of primitive types. In the Type property of an attribute, you are provided with a filtered list that shows simply the primitive types of the language declared for that class.

Reference types are class types, interface types, and array types. To select a reference type, place your cursor in the type cell for an attribute, right-click, and select Choices. You are provided with a dialog that presents all classes in the encyclopedia, which you can select and drag into the class attribute's type cell.

Specifies that a parameter is a constant.

Specifies that the variable is vulnerable to thread access. It is read from memory each time it is used and stored to memory after each occasion, to ensure data integrity. You cannot declare a variable to be both final and volatile.

Specifies that the caller can modify the variable's value. The syntax is: ..., ByRef parameter, ... Used primarily in the VB language.

Specifies that a parameter is optional, and it is passed by reference. Used primarily in the VB language.

Specifies that a parameter is passed by value rather than by reference. This implies that the caller cannot modify that variable's value. The syntax is: ..., ByVal parameter, ... Used primarily in the VB language.

Specifies that a parameter is optional, and it is passed by value. Used primarily in the VB language.

Specifies that a variable is passed by pointer. Used in the C++ language.

Specifies that a variable is passed by a pointer to a pointer. Used in the C++ language.

Specifies that a variable is passed by reference.

Specifies that a parameter is passed by value. The syntax is: ..., (parameter), ... An example is: ShowDialog (i), which calls a function ShowDialog and passes it the variable 'i', by value.

Specifies that the variable is vulnerable to thread access. It is read from memory each time it is used and stored to memory after each occasion, to ensure data integrity. You cannot declare a variable to be both final and volatile.

Specifies that a parameter is a constant and passed by pointer. Used in the C++ language.

Specifies that a parameter is a constant and passed by a pointer to a pointer. Used in the C++ language.

Specifies that a parameter is a constant passed by reference. Used in the C++ language.

Specifies that a parameter is volatile and passed by pointer. Used in the C++ language.

Specifies that a parameter is volatile and passed by a pointer to a pointer. Used in the C++ language.

Specifies that a parameter is volatile and passed by reference.

You can specify that the attribute is derived from a superclass.

In System Architect you can map a Class diagram to a Logical ER diagram. However, the Logical ER diagram knows only of generic ANSI data types. System Architect will automatically map the data types of the target language of the class attribute (that is, Java, C++, and so on) to the best equivalent ANSI-generic data type. If this mapping is not sufficient, you can also specify, for each class attribute, an underlying data element. This data element can have an ANSI-generic data type specified. When mapping the class diagram to a data model, if a class attribute has an underlying data element specified, it will be the data element that will be mapped to the ER diagram.

Specifies that the attribute is a primary key. This is an extension to UML modeling, and is used when mapping the class to a data model.