主键、引用完整性和检查约束。
XML验证检查约束。
允许您为表创建表检查约束。
The check constraints view allows you to create table check constraints for the table.
用户可以使用检查约束来加强对xml列的验证。
A user can enforce validation on an XML column using check constraints.
对检查约束进行解析，但是不强制实施。
利用检查约束和引用约束删除无效连接。
Removing unproductive joins with informational check and referential constraints.
另一种方法是通过在昵称上定义检查约束来指定分区谓词。
Another alternative is to specify partitioning predicates by defining check constraints on nicknames.
DB 2 V 9.5支持对xml值进行检查约束。
提供了包含智能感知功能的SQL编辑器控件来编辑检查约束表示。
The SQL editor control that contains intellisense capabilities is provided to edit the check constraint expression.
Checkconstraints视图允许为表创建表检查约束。
The Check constraints view allows you to create table check constraints for the table.
还存在一个包含智能能力的SQL编辑器控件，用于编辑检查约束表达式。
There is also a SQL editor control that contains intellisense capabilities to edit the check constraint expression.
这一类的开销包括检查约束验证和外键约束(参照完整性(RI))验证。
This category of overhead includes CHECK constraint verification and foreign key constraint (referential integrity (ri)) verification.
Checkconstraints视图—允许添加表及其列的检查约束。
Check constraints view a "Allows adding check constraints for a table and its columns."
接下来的例子展示了如何在更复杂的例子中使用检查约束和引用约束。
The next example shows how check and referential constraints are used in a more complex example.
上面创建的检查约束总是会检查是否根据customer模式对文档进行了验证。
The check constraint created above always checks that the document is validated according to the customer schema.
显然，检查约束的使用对性能有一点小小的影响，但是外键和触发器的影响却非常大。
Clearly the use of check constraints has a minor effect on performance, but foreign keys and triggers can be extremely significant.
MTK 将ENUM数据类型映射到带检查约束的VARCHAR(255)。
MTK maps the ENUM data type to VARCHAR(255) with check constraint.
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。
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.
如果远程表在数据上有检查约束，那么可以使用信息检查约束将这些约束传递到联邦服务器。
If the remote tables have restrictions on the data such as check constraints, you can convey these restrictions to the federated server using informational check constraints.
当想在第21行进行合并时，会得到结果0rowsmerged因为检查约束发生了冲突。
When you try to merge at line 21, you get the result 0 rows merged because the check constraint is violated.
触发器并不像参照完整性约束和检查约束那样，我们甚至可以使用对其他表来进行更新。
Triggers, unlike referential and check constraints, can even be used to update other tables.
清单9中的代码将会修改 清单8中创建的表customer，以对表执行检查约束
The code in Listing 9 alters the table customer created in Listing 8 to put a check constraintson the table
给items和suppliers的定远程表定义，便可以用以下语句声明相应昵称上的检查约束。
Given the remote table definitions for items and suppliers, you can declare check constraints on the corresponding nicknames with the following commands.
表items和SUPPLIERS分别在列item_id和suppl_id上定义了检查约束。
Both tables ITEMS and SUPPLIERS have check constraints defined on columns item_id and suppl_id respectively.
例如，表可能依赖于用户定义的不同类型；检查约束依赖于函数；视图依赖于视图、别名和函数；等等。
For example, tables may depend on user-defined distinct types; check constraints depend on functions; views depend on views, aliases, and functions; and so on.
检查约束(checkconstraint)是一类可以在创建表时作用到表列的约束。
A check constraint is a type of constraint which can be put on a table column at the time of the creation of the table.
重写阶段将使用四个昵称上定义的引用约束和检查约束来删除连接操作和一个UNION分支。
The rewrite phase will use the referential and check constraints defined on the four nicknames to eliminate the join operations and one of the UNION branches.
也可以使用系统编目视图来检索关于NOT NULL、惟一、主键、外键和表检查约束的信息。
You can also use the system catalog views to retrieve information about NOT NULL, unique, primary key, foreign key, and table check constraints. For example.
在ETL过程中，即时参照完整性和检查约束极其有助于检测数据问题，在最终的数据仓库表中实现它们也不会高效。
Even though referential integrity and check constraints are very helpful during the ETL process to help detect data problems, implementing them on final data warehouse tables is not efficient.
如果在表的xml列上存在XML验证检查约束，在手动更新或者通过触发器更新之前，用户可能需要验证新的xml值。
If an XML validation check constraint exists on the XML column of the table, the user may need to validate the new XML value before the update either manually or by creating a trigger.
应用推荐