逻辑数据模型中的每个实体都被指定了一个主键。

Each entity in the logical data model is assigned a primary key.

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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.

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实体具有主键。

The entity has a primary key.

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实体具有主键。

The entity has a primary key.

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