还可以为具有组合键的实体创建一个主键类。
You can also create a primary key class for entities that have composite keys.
我们还使用由组成ejb主键的值构建的主键类使得把主键指定为一个单独的实体很容易。
We also use a primary key class, constructed from the values comprising the EJB primary key, to make it easy to specify the primary key as a single entity.
EJB规范的 2.0版将主键类定义成任何是 RMI-IIOP中合法值类型的类。
Version 2.0 of the EJB specification defines a primary key class as any class that is a legal value type in RMI-IIOP.
要转换一个已有的列成为一个主键，在图中点击这个列(类中的属性)。
To convert an existing column into a primary key, click on the column (property in the class) in the diagram.
在从LDM转换到类模型时，有些语义可能会丢失，因为LDM的数据语义比类模型更加丰富(例如主键)。
Some semantics can be lost during the transformation from an LDM to a class model because LDMs hold richer data semantics (as in, primary keys) than class models.
连续数字在oltp类应用程序中常常用于生成关系模型所需的主键。
Sequential Numbers are often used in OLTP-like applications to generate primary keys required by the relational model.
此外，注意主键和外来键属性是怎样表达车辆调度类图的关系的。
Also, notice how the primary key and foreign key properties represent the relationships on the Deals on Wheels class diagram.
例如，如果想消除显示在组合框中的主键的泄漏，只要在airline类中添加toString方法就可以，如清单6所示。
For example, getting rid of the leaky primary key that shows up in the combo box is as easy as adding a toString method to the Airline class, as shown in Listing 6.
Entity类需要一个主键。
表必需与属性定义匹配，例如，等式表的主数据库键必须也是 Persistent类的主键。
The table must match the definition of your attributes; for example, the primary database key for the equations table must be the primary key of the Persistent class as well.
第41 - 54行说明了如何通过使用包含在WASv5WSAExtensions . jar库中的EPRHelper实用类来从epr创建主键。
Lines 41-54 shows how the primary key is created from an EPR by making use of the EPRHelper utility class, included in the WASv5WSAExtensions.jar library.
find方法要求您知道主键和实际类的类型。
The find method requires you to know the primary key as well as the actual class type.
该键类包含bean的唯一主键实现。
The key class contains the unique primary key implementation for the bean.
名称属性在customer类映射到的表上定义外键，参考列定义Table CustomerOrder映射到的主键。
The name attribute defines the foreign key on the table to which the Customer class is mapped, and the referenced column defines the primary key to which the table CustomerOrder is mapped.
而不是依赖你主键字段的命名假设上，或在你的Employee类中的冗余定义(例如，set _ primary_key'X ')，DrySQL从你数据库信息schema中提取雇员表中的主键。
Set_primary_key 'X', DrySQL retrieves the primary key specification for your Employees table from your database's information schema.
对于实体类，必须至少有一个成员具有此特性，并应映射到相应表或视图中的主键或唯一键。
For an entity class, at least one member must have this attribute and should be mapped to the primary key or a unique key in the corresponding table or view.
对于实体类，必须至少有一个成员具有此特性，并应映射到相应表或视图中的主键或唯一键。
For an entity class, at least one member must have this attribute and should be mapped to the primary key or a unique key in the corresponding table or view.
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