Run rake db:migrate to create the SUBSCRIPTIONS table and add foreign key columns to SUBJECTS.

运行rakedb:migrate以创建SUBSCRIPTIONS表并将外键列添加到SUBJECTS 中。

youdao

You also need to add a foreign key 'user_id' to the DOCUMENTS table so you know the user who uploaded a particular document.

另外还需要添加一个外键' user_id '到documents表中，以便知道哪个用户上传某个特定的文档。

youdao

In this section, the file containing the generated DDLs is further edited to add the required foreign key statements. This is in order to define the tables relationships.

在本节中，我们将进一步编辑包含生成的DDL的文件，以添加所需的外键语句，从而定义表关系。

youdao

Run rake db: migrate to create the SUBJECTS table and add the subject_id foreign key.

运行rakedb：migrate，以创建subjects表并添加subject _ id外键。

youdao

You'd need to create a new table and also add a new column representing the foreign key to each article to point to a blog.

需要创建一个新表，还要添加指向blog的每个文章的外键。

youdao

In the foreign keys page (shown in Figure 3), add a new foreign key ord_cust_key.

在外键页面中(如图3所示)，增加一个新的外键ord_cust_key。

youdao

To do so, click on the Add icon, and then select the database object type Foreign Key Constraint, as shown in Figure 4c.

为此，单击add图标，然后选择数据库对象类型Foreign KeyConstraint，如图4c所示。

youdao

The article shows one solution that we add triggers to simulate the primary key and foreign key, and then realize cascade update.

本文介绍了一种通过增加触发器来模拟主外键，实现级联更新功能的方法。

youdao

The article shows one solution that we add triggers to simulate the primary key and foreign key, and then realize cascade update.

本文介绍了一种通过增加触发器来模拟主外键，实现级联更新功能的方法。

youdao