您可以在任何数据库中进行快速测试来确认这一点，方法是打开一个视图，然后按向下箭头键。
You can do a quick test to confirm this in any database by opening a view and then pressing the down arrow.
第二，我们将直接在位于数据库根的键下面存储然后删除一些简单的值和数据结构。
Second, we will store and then delete some simple values and data structures directly under keys at the database root.
对于一对一关联，开发者必须选择关联的哪一端持有代表另一端的外键(这会向下传给数据库模式)。
For one-to-one associations, developers have to select which end of the association holds the foreign key that represents the other end (this gets propagated down to the database schema).
在一个非分区数据库中，不需要分区键或分区映射。
In a non-partitioned database, no partitioning key or partitioning map is required.
许多数据库会自动对这些键施加约束，以便值真正匹配另一个表中的一条记录，这有助于摆脱这一困难。
Many databases will enforce constraints on these keys automatically so that value actually matches a record in the another table, which can help this out.
如果不需要特别考虑并置，那么能使数据均匀地散布在数据库分区组中所有数据库分区上的分区键就是好的分区键。
If collocation is not a major consideration, a good partitioning key for a table is one that spreads the data evenly across all database partitions in the database partition group.
这个标识符(通常是数据库键)能够作为该url参数之一而生成并发送到客户机。
This identifier, most often a database key, can be generated and sent to the client as one of the URL parameters.
键/值数据库的突然流行。
关系数据库中的关系是通过使用外键来维护的。
Relationships in relational databases are maintained through the use of foreign keys.
应用程序对象所使用的键应该嵌入到规则中，在具有规则库的情况下，请确保无法轻易地对该键进行更改。
The key used for your application object will be embedded in your rules, making it difficult to change once you have a library of rules.
然后它用它的双亲请求，根据连接的描述找到正确的数据库统计值，并根据sql键字符串找到语句统计值。
It then USES its parent request to find the right database statistics based on the connection's description, and to find statement statistics based on the SQL key string.
此外，组合键倾向于将您的数据库和OR M设计绑定到原始领域。
Also, they tend to tie your database and ORM design to the original domain.
在满足筛选器条件的每个行中，数据库服务器将对键应用哈希函数，并探测哈希表以查找匹配的键值。
For each row that satisfies the filter condition, the database server applies hash function to the key and proves the hash table to find a match.
本技巧从问题的简单的描述开始：定义组合数据库键。
This tip starts with a simple description of the problem: defining a composite database key.
该创建类似于1个简单规则创建，但它展示了在每个事件流发生时使用映射键从数据库获取字段需要额外的性能开销。
This scenario is similar to the 1 simple rule scenario, but shows the additional performance cost of using a mapped key to retrieve a field from the database on every event flow.
虽然这也许看来直接类似于关系数据库的键机制，但是有一个重要的差异：大多数解析器都将这些指针看作是单向的。
While this may seem to be directly analogous to a relational database's key mechanisms, there's one important difference: Most parsers treat these Pointers as unidirectional.
对于这些键，应用程序可以针对相关数据库运行查询来查找包含匹配的完整记录。
Given those keys, an application can run a query against the associated database to find the complete records that comprise the match.
就像城市地图按网格分成一些区一样，数据库管理器使用分区键来确定数据所存储在的位置(数据库分区)。
Just as a city map is organized into sections using a grid, the database manager USES a partitioning key to determine the location (the database partition) where the data is stored.
在设置一个值后，键就从数据库中移除掉，并添加一条具有更新过的值的新记录。
Then when a value is set, the key is removed from the database and a new record is added with the updated value.
GAE数据存储中的键也是惟一的，正如在传统的数据库中一样。
Keys in the GAE datastore are also unique, just as they would be in a traditional database.
将选择电影标题背后的原始逻辑作为数据库的键。
Take the original reasoning behind selecting movie title as the key for the database.
这个数组以数据库列名作为数组键，以数据库字段值作为数组值。
This array contains the database column names as the array keys and the database field values as the array values.
这样使得在关系数据库模型中导入外键更方便。
This makes importing foreign keys easier in relational database models.
从清单2的输出，您可以看到在数据库中有三个键。
From the output of Listing 2, you can see that there are three keys in the database.
早期的企业应用程序使用数据库表和表之间的外键关系进行实体建模。
Early enterprise applications used database tables and foreign-key relationships between them to model entities.
它只是返回一个值0作为交易订单的键，而不会更改数据库。
It will simply return a value of 0 as the key to the trade order without changing the database.
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.
但和数据库不同的是，本地的唯一键还不行。
Unlike in the case of a database, however, a locally unique key will not do.
答题者的姓名作为查询储存库的键。
The names of the respondents serve as keys to query the repository.
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