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.
checks为每个表检查约束保持一个行db2select constname,tabname,textfrom syscat . checks。
Syscat.checks Contains a row for each table check constraint db2 select constname, tabname, text from syscat.checks.
COLCHECKS为表检查约束所引用的每个列保持一个行db2select constname,tabname,colname,usagefrom syscat.colchecks
SYSCAT.COLCHECKS Contains a row for each column that is referenced by a table check constraint db2 select constname, tabname, colname, usage from syscat.colchecks
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.
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.
对一个表XML值应用before trigger和检查约束，往往可以确保 XML 值对于指定模式是有效的。
The before trigger and check constraint on a table XML value always ensures that the XML values are valid as per the specified schema.
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.
tabconst为每个唯一性(U)、主键(p)、外键(f)或者表检查(K)约束保持一个行db2select constname,tabname,typefrom syscat . tabconst。
Syscat.tabconst Contains a row for each unique (u), primary key (p), foreign key (f), or table check (k) constraint db2 select constname, tabname, type from syscat.tabconst.
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.
TABLESCHECKCOUNT 该表所定义的检查约束的数量db2 "select tabname, checkcount from syscat.tables where checkcount > 0"
SYSCAT.TABLES CHECKCOUNT Number of check constraints defined on this table db2 "select tabname, checkcount from syscat.tables where checkcount > 0"
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."
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.
我们建立一定的时间表、约束条件、检查点，和通信程序，但我们将细节留给第三方。
We establish certain timetables, constraints, checkpoints, and communication procedures; but we leave the details to the third party.
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.
尽量减少表上的触发器、检查和外键约束以及生成的列。
Minimize the triggers, CHECK and foreign key constraints, and generated columns for the table.
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.
示例代码xmlcheckconstraint . db 2演示了如何为具有相同结构的不同表创建视图，该视图可以进行检查约束，以及按模式对表进行划分。
The sample code xmlcheckconstraint.db2 demonstrates how users can create a view on the different tables with same structure with check constraints and implement partitioning of tables by schema.
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
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.
在Oracle10g中，如果表上同时存在BEFORE INSERT触发器和NOT NULL约束，那么先执行BEFORE触发器，然后执行约束检查。
In Oracle 10g, if there is a BEFORE INSERT TRIGGER and a NOT NULL constraint on a table, then the BEFORE TRIGGER is executed first, and then the constraint check is performed.
检查条件约束可指定在资料表中为一或多个资料行所接受的资料值或格式。
A check constraint specifies the data values or formats that are acceptable in one or more columns in a table.
检查条件约束可指定在资料表中为一或多个资料行所接受的资料值或格式。
A check constraint specifies the data values or formats that are acceptable in one or more columns in a table.
应用推荐