Rails USES the primary key column id for various recordkeeping and referencing tasks.

Rails使用主键列id来完成各种记录保持和引用任务。

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In Listing 5, you have a standard primary key column called PO_ID (that is, purchase order ID).

在清单5中，您有一个称为PO_ID的标准主键列(即订单id)。

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Note, however, that we cannot update the primary key columns or any other key columns that you declare; in this case, EMP_ID is a primary key column.

但是请注意，我们不能修改您声明的主键列或任何其他的键列；在本例中，EMP _ ID是主键列。

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If informational check constraints exist on the primary key column, you should explicitly specify informational check constraints on their corresponding foreign key columns. For example.

如果在主键列上存在信息检查约束，那么应该在它们相应的外键列上指定信息检查约束。

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It sets up two accessors: accessor 0 contains only the primary key column (ID) and accessor 1 contains other columns.

它设置两个访问器：访问器0仅包含主键列id，访问器1包含其他列。

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In this type of table, you define a primary key column, a MIME type column, and one or more generic columns as BLOB data.

在这种类型的表中，你定义了一个主键列，一个MIME类型列，和一个或多个通用列用来表示BLOB数据。

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You also want to be able to write data to all the columns except the primary key (because you cannot write to the primary key column).

还希望能够将数据写入除主键外（因为不能向主键列写入）的所有列。

youdao

You also want to be able to write data to all the columns except the primary key (because you cannot write to the primary key column).

还希望能够将数据写入除主键外（因为不能向主键列写入）的所有列。

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