确保每个表都有一个主键。

Make sure each table has a primary key.

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表中的每个记录都有一个惟一的ID，称为主键。

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

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注意这个表有两个主键。

Note that this table has two primary keys.

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目标表必须有一个主键。

The target table must have a primary key.

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要实现更好的复制，ER要求表定义一个主键。

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

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第二个（ REF_ESTATE_ID）是另外一个表的主键的列名。

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

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第一列(ID)是此表的主键。

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

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行键是表的主键，通常是一个字符串。

The row key is the primary key of the table and is typically a string.

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您可以回想一下，创建db2表时指定了account_num列作为主键。

If you recall, your DB2 table was created specifying the primary key of the ACCOUNT_NUM column.

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允许您定义表的主键、惟一键和外键。

The keys view allows you to define primary, unique, and foreign keys for the table.

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还将ID列标识为表的主键。

You've also identified the id column as the table's primary key.

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每个表有一个用作主键的id字段。

Each table has an id field that serves as the primary key.

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所以，在book表这个示例中，有一个主键字段叫做book_id。

So, in the case of the book table, there is a primary key field called book_id.

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keys视图允许定义表的主键、惟一键和外键。

The keys view allows you to define primary, unique, and foreign keys for the table.

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步骤5：向表添加主键。

Step 5: Adding a primary key to a table.

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事实上这是dw_authors表的主键，因此必须有。

In fact, it's the primary key of the dw_authors table, so it must exist.

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Time表的主键是 date_time。

The Time table has primary key date_time.

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location表的主键是location_id。

The location table has primary key location_id.

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customer表的主键是cust_num。

The Customer table has primary key cust_num.

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通常，源表的主键值是一个很好的选择。

Usually, the primary key field of the source table makes a good choice.

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表必须具有相同的主键、唯一索引或唯一约束。

Tables must have the same primary key, unique index, or unique constraint.

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唯一约束是表的主键，因此不能移除。

Can't remove unique constraint since it's the primary key of a table.

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为什么删除主键会影响所有的表行吗？

Why does DROP PRIMARY KEY affects ALL table rows?

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我们已与公司的名字和数字主键标识表。

We have table with companies names and a numeric primary key identity.

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当保存表时，主键将在数据库中进行更新。

The primary key is updated in the database when you save your table.

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该列必须至少在一个表中是主键。

The column must be a primary key in at least one of the tables.

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一个表只能有一个主键。

A table can have only one primary key.

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表通常包括一个主键，该主键确保每个行都是唯一的。

A table usually includes a primary key that ensures every row is unique.

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该表已为自动编号主键。

This table has autonumber as the primary key.

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输入分配给该表的主键的列。

Enter the columns contributing to that table's primary key.

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