What Is an Entity Attribute?

An attribute is a named characteristic of an entity object or view object, implemented as a JavaBean property of the object class. An entity attribute can correspond to a database column, or be independent of a column, and describes the values that the entity object can hold.

Two kinds of entity attributes

There are two kinds of entity attributes:

Attribute kind

Value is derived from and stored in the database?

persistent

yes

transient

no

Attribute kind	Value is derived from and stored in the database?
persistent	yes
transient	no

Persistent entity attributes correspond to database columns

When you first create an entity object using reverse generation, a persistent entity attribute is created for each table column.

For forward generation, when you create database tables from entity objects, each persistent attribute becomes a column in the table.

After, if you change a table or entity objects, you can use the Synchronize tool to make sure that the tables and entity objects are in sync.

Entity attributes have settings

Entity attribute settings control the Java type of the attribute, represent column constraints such as PRIMARY KEY, NOT NULL or UNIQUE, control the properties of generated database columns, and perform miscellaneous simple functionality such as specifying static default values.

All of the attribute settings are stored in the entity object XML file.

Entity attributes are based on the UML definition

In Business Components for Java, the term "attribute" is based on the UML definition of the term, not the XML definition. In UML, an attribute is a named property of a class that describes a range of values that instances of that class might hold.