这些键值可以存储在现有的数据表中或者存储在单独创建的称作外键表的表中。
These keys can be stored in an existing data table or in a separately created table referred to as the external key table.
当使用外键时(ei列被存储在它们自己的表中)，可以在外键表中找到孤立的记录并将其转化为删除存根。
When external keys are in use (ei columns stored in their own table), we are able to find the orphaned record in the external key table and turn it into a deletion stub.
对于一对多关系，外键表是靠近线的无穷符号的那个表。
For a one-to-many relationship, the foreign-key table is the table near the line's figure-eight symbol.
索引下推使用下推键执行事实表外键索引的查询。
An index pushdown USES the pushed-down keys to perform index lookups on a foreign key index of the fact table.
当将数据分解成多个具有外键关系的表时，这尤其重要。
This is important when data is decomposed into multiple tables having foreign key relationship.
在包中显示事实表的外键。
我们的虚拟外键基于TB_RIGHT表的两个列。
Our virtual foreign key is based on two columns from the TB_RIGHT table.
事实表可以根据一或多个外键过滤。
The fact tables can be filtered on one or more of their foreign keys.
运行rakedb:migrate以创建SUBSCRIPTIONS表并将外键列添加到SUBJECTS 中。
Run rake db:migrate to create the SUBSCRIPTIONS table and add foreign key columns to SUBJECTS.
给 Transformer建模师提供事实表中发现的外键。
Expose foreign keys found in fact tables to Transformer modelers.
SQLObject允许将表之间的关系定义为外键。
SQLObject lets you define relationships among tables as foreign keys.
确保参照完整性(referential integrity,ri)关系中的依赖表拥有与外键匹配的索引。
Ensure dependent tables in a referential integrity (ri) relationship have indexes that exactly match the foreign key.
CheckOutRecord对象使用支持此模型的 CheckOutRecord表中的外键将特定的用户链接到保留的系统。
The CheckOutRecord object links a particular user to a reserved system using foreign keys in the CheckOutRecord table that backs this model.
如果使用的是MySQL，而且想要为表定义外键，则需要在从数据库中加载模式之后，编写代码定义这些字段。
If you're using MySQL and want to define foreign keys for a table, you'll need to define those fields in code after loading the schema from the database.
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。
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.
一个一对多关联被映射到“many ”表的一个外键。
A one-to-many association is specifically mapped to a foreign key in the "many" table.
列pdb_id是一个外键，链接了原子坐标与pdbxml表中对应的PDBML文档。
The column pdb_id is the foreign key that links atom coordinates to the corresponding PDBML document in the PDBXML table.
一般情况下，事实表中的外键不会出现在IBMCognosBI模型的事实查询主题中，如下图所示。
Typically, foreign keys found in the fact table are not presented in the fact query subjects in an IBM Cognos BI model as seen below.
每个一对一的关联在表中任一类中充当外键。
Each one-to-one association is buried as a foreign key in the table of either class.
一个一对一关联被映射到表中的一个外键(无所谓哪个)？
A one-to-one association is mapped to a foreign key buried in one of the tables (no matter which)?
这里我们看到Customer的Address字段映射用表模式文件中的外键引用将关系的两部分链接在一起。
Here we see that the mapping for Customer's Address field links the two halves of the relationship together with the foreign key reference in the table schema file.
但是从我们数据模型的角度来看，我们没有一个惟一的表可以用来创建我们的外键约束，就像TB_RIGHT和TB_PERSON之间那样。
But from our data model's perspective, there is no unique table we can use to create our foreign key constraint, like the one between TB_RIGHT and TB_PERSON.
在清单2中我的location表中，我提供了一个指向account的外键。
In my location table in Listing 2, I provide a foreign key back to account.
为了更好地理解这一点，我们回到world数据库并考虑它的两个表Country和City，此二者通过code外键相互链接在一起。
To better understand this, let's return to the world database and consider two of its tables, Country and City, which are linked to each other via the code foreign key.
对于具有引用另一个表的外键的表，可以使用此方法。
You can use this method on tables that have a foreign key that references another table.
然而，不管是父表还是子表，目前还不支持复制外键。
However, it does not currently support copying of foreign keys, either parent or child.
索引下推只需要事实表的单列索引，虽然在所需的外键列是索引的第一个键的情况下可以使用多列索引。
Index push-downs require only a single-column index on the fact table, although they can use a multi-column index if the required foreign-key column is the first key in the index.
了解关系数据库、数据模型、惟一键、主键、外键和表联结。
Learn about relational databases, data models, unique keys, primary keys, foreign keys, and table joins.
联合表：(可选)将子类映射到与父类映射到的表具有外键关系的表。
Joined table: (Optional) the child class is mapped to a table that has a foreign key relationship to the table to which the parent is mapped.
维度表需要作为主键数据的通用键；这将作为事实表的外键。
A dimension table needs a generalized key as the primary key data; this becomes the foreign key in the fact table.
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