什么是实体对象实例？

Question

I understand that Entity Object Definition is XML data that represents metadata and corresponds to DB table.

Example:

 <Entity
   xmlns="http://xmlns.oracle.com/bc4j"
   Name="Departments"
   Version="11.1.1.53.3"
   DBObjectType="table"
   DBObjectName="DEPARTMENTS"
   AliasName="Departments"
   BindingStyle="OracleName"
   UseGlueCode="false">
  <DesignTime>
   <AttrArray Name="_publishEvents"/>
  </DesignTime>
 <Attribute
   Name="DepartmentId"
   IsNotNull="true"
   Precision="4"
   Scale="0"
   ColumnName="DEPARTMENT_ID"
   SQLType="NUMERIC"
   Type="oracle.jbo.domain.Number"
   ColumnType="NUMBER"
   TableName="DEPARTMENTS"
   PrimaryKey="true">
  <DesignTime>
   <Attr Name="_DisplaySize" Value="22"/>
  </DesignTime>
 </Attribute>

I understand that Entity Attributes corresponds to DB table columns.

BUT I CAN`T understand what is Entity Object Instance. I know that it corresponds to one single row from DB table and for every row there is a different EOI, but where can I find it? Any example and simple explanation would be helpful! :)

Answer 1

Entity Object Instance is something like the row data & business logic object oriented representation. Imagine you need to load data from a DB table into memory, you need a collection of rows (for example List<DbTableRow> ), each row ( DbTableRow ) is an object that contains properties according to each table column data types and it's values; Entity Object Instance is something like each DbTableRow object item of the list. Hope it helps...

Answer 2

The following URL will have examples about ADF Entity Object

About Entity and View Object

Entity and View Java classes

I know this is an old post. Hope it will be useful for others