对于使用Oracle数据库的类图，使用以下步骤:

File→Data Modeler→Import→Data Dictionary→select DB connection→Next→select database->select tables ->完成

它很容易去文件-数据建模器-导入-数据字典- DB连接- OK

您可以参考一个名为Oracle Data Modeler的配套工具。网站上有在线演示，可以让你开始学习。它曾经是一个额外的费用项目，但我注意到它再次是免费的。

从Data Modeler概览页面:

SQL Developer Data Modeler is a free data modeling and design tool, proving a full spectrum of data and database modeling tools and utilities, including modeling for Entity Relationship Diagrams (ERD), Relational (database design), Data Type and Multi-dimensional modeling, with forward and reverse engineering and DDL code generation. The Data Modeler imports from and exports to a variety of sources and targets, provides a variety of formatting options and validates the models through a predefined set of design rules.

从SQL Developer 3开始，它就非常简单了(他们可以让它变得更简单)。

Go to «View → Data Modeler → Browser». The browser will show up as one of the tabs along the left-hand side. Click on the «Browser» tab, expand the design (probably called Untitled_1), right-click «Relational Models» and select «New Relational Model». Right click on the newly created relational model (probably Relational_1) and select «Show». Then just drag the tables you want (from e.g. the «Connections» tab) onto the model.  Note when you click on the first table in the Connections tab, SQLDeveloper opens that table in the right: select all the tables from the left, then ensure the Relational_1 tab (or whatever name) is the active one in the rhs before you drag them over, because it has probably switched to one of the tables you clicked in the lhs.

使用Oracle SQL Developer创建实体关系图:

文件→数据建模器→导入→数据字典→选择数据库连接→下一步→选择模式/数据库类型→下一步→选择导入对象→下一步→生成设计→完成

对于使用Oracle数据库的类图，使用以下步骤:

File→Data Modeler→Import→Data Dictionary→select DB connection→Next→select database->select tables ->完成