Recreate the primary key.

重新创建主键。

So what is a primary key?

那么什么是主键？

An Entity class needs a primary key.

Entity类需要一个主键。

Customer ID column (as primary key).

客户id列(作为主键)。

Make sure each table has a primary key.

确保每个表都有一个主键。

The primary key identifying the catalog

标识 Catalog 的主键。

The target table must have a primary key.

目标表必须有一个主键。

The Time table has primary key date_time.

Time 表的主键是 date_time。

Leave the primary key empty and click Next.

留下空的主键，并点击Next。

This happens when no primary key is defined.

即使没有定义主键，这种操作也会发生。

The Customer table has primary key cust_num.

customer表的主键是cust_num。

The location table has primary key location_id.

location表的主键是location_id。

This becomes the primary key in the physical model.

这成为物理模型中的主键。

Primary key, referential integrity, and check constraints.

主键、引用完整性和检查约束。

The first column (ID) is the primary key of the table.

第一列(ID)是此表的主键。

Automatic primary key and unknown primary key generation.

自动生成主键和未知的主键。

Returns one particular book identified by its primary key.

返回一本特定的、由其主键(primary key)标识的书籍。

In this case, there is no primary key available in the EPR.

在这个范例中，EPR中没有可用的主键。

This surrogate column can be designated the primary key column.

可以将该代理列指定为主键列。

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

逻辑数据模型中的每个实体都被指定了一个主键。

Every record in the table has a unique ID called the primary key.

表中的每个记录都有一个惟一的ID，称为主键。

This is analogous to making a column in a database a primary key.

这类似于数据库中选择一列作为主键。

They use database-generated primary key values for the ID attribute.

它们为 ID 属性使用数据库生成的主键值。

The DAO may allow queries based on criteria other than the primary key.

DAO可允许基于除主键之外的标准进行查询。

As we mentioned above, they all have a column named ID as a primary key.

前面我们提过，它们都有一个叫作id的列，并将该列作为主键。

Updates the attributes of a specific book that is identified by its primary key.

更新一本特定的、由其主键标识的书籍的属性。

To help with replication ER requires that the table have a primary key defined.

要实现更好的复制，ER要求表定义一个主键。

You will notice that only STATE is still selected, because it is the primary key.

您将会注意到，只有STATE仍然被选中，因为它是主键。

The second (REF_ESTATE_ID) is the column name from the other table's primary key.

第二个（ REF_ESTATE_ID）是另外一个表的主键的列名。

Each record saved in the datastore, also called an entity, requires a primary key.

保存在数据存储中的每一条记录，即实体，都需要有一个主键。