mqt

The MQT feature provides various options for doing this to suit various operational needs .

MQT特性为适应各种运营需求而进行更新提供了多种选项。

An MQT is a table whose definition is based on the result of a query .

MQT是基于一个查询的结果而定义的表。

Of particular interest here , are the available MQT refresh policies .

比较特别的是，这种情况下可以使用MQT刷新策略。

You can think of an MQT as a kind of materialized view .

您可以将MQT看作一种物化的视图。

A customer experiences performance issue while refreshing an MQT as part of a batch run .

在批处理运行过程中，当刷新一个MQT时，客户会遇到性能问题。

DB2 can automatically rewrite a query to take advantage of an MQT .

DB2可以自动地重写查询以使用MQT。

However , the design of an MQT can be affected by which partitioning features are used on the base table .

然而，MQT的设计却可能受到基本表上使用的分区特性的影响。

An MQT can be defined at table creation time as maintained by the system or maintained by the user .

MQT可以在创建表时定义，或者定义为系统维护的MQT，或者定义为用户维护的MQT。

As the data for the base table ( s ) changes , the MQT needs to be updated accordingly .

当基本表中的数据发生改变时，需要相应地更新MQT。

Avoid inserting to tables with " refresh immediate " MQT 's based on them .

避免将行插入到带有“refreshimmediate”MQT的表中。

In fact , the support of statistical view shares some similar limitations to the support of MQT in DB2 .

实际上，DB2中对统计视图的支持与对MQT的支持具有类似的局限性。

For example , an MQT can be partitioned using MDC or TP .

例如，可以使用MDC或TP对MQT分区。

A materialized query table ( MQT ) is a table whose definition is based upon the result of a query .

物化查询表（MQT）是一种以一次查询的结果为基础定义的表。

Generally , ETL processes manually specify when to update MQT rather than allow this to happen automatically .

通常，ETL过程是手动地指定何时更新MQT，而不是让更新自动发生。

This article introduced the following DB2 table design features : table partitioning , MDC , DPF , and MQT .

本文介绍了以下DB2表设计特性：表分区、MDC、DPF和MQT。

Maintenance of MQT Series Coalmine Pneumatic Roof Bolter

MQT系列矿用气动锚索钻机的维护

For example , an MQT can be created on one or more tables that uses MDC and TP .

例如，可以在一个或多个使用MDC和TP的表上创建MQT。

The statistical view is kind of like the Materialized Query Table ( MQT ), except that there is no need for materialization .

统计视图有点类似于物化查询表（MaterializedQueryTable，MQT），不同的是统计视图不需要物化。

The data that is contained in an MQT is derived from one or more tables on which the materialized query table definition is based .

包含在物化查询表中的数据来自定义物化查询表时所基于的一个或多个表。

This way , queries accessing the MQT will return the same result throughout the day even though the underlying data is being updated periodically .

因此，即使底层的数据是周期性地更新的，访问MQT的查询全天返回的都是相同的结果。

You can specify for example what REOPT options to use , or what MQT table to consider or what query optimization to use .

例如，可以指定使用哪个REOPT选项，使用哪个MQT表，或者使用什么样的查询优化。

A query against this MQT right after it was created , but before the REFRESH TABLE statement was issued , returns an error .

当这个MQT刚创建且还没有发出REFRESHTABLE语句的时候，对它的查询将返回一个错误。

Not supported are range clustered tables ( RCT ), materialized query tables ( MQT ), and typed tables .

不支持范围簇表（RCT）、物化查询表（MQT）和有类型的表。

The MQT refresh is triggered when the table tab2 involved in its definition is populated .

当为MQT定义中涉及的表tab2填充数据时，就会触发对MQT的刷新。

Another way to provide a new and better access path for a query is through the use of DB2 's materialized query table ( MQT ) functionality .

为查询提供更好的访问路径的另一种方法是使用DB2的物化查询表（MQT）功能。

Next , to populate the MQT with some data , we will import data that had been exported from the EMPLOYEE and SALES tables .

接下来，为了填充数据到MQT中，我们将导入从EMPLOYEE和SALES表中导出的数据。

We suggest running Explain against your inserts that involve MQT 's , to be aware of what 's happening behind the scenes .

我们建议对于涉及MQT的insert运行Explain，以便清楚幕后情况。

The MQT refresh time is now reduced , because often only the small MQTs based on [ CurrentMonthSales ] must be refreshed .

MQT重新刷新时间减少，因为通常仅需重新刷新基于[CurrentMonthSales]的小MQT。

For example , if the base table is DPF partitioned , the design of the MQT should consider whether to replicate the MQT across the data partitions .

例如，如果基本表使用了DPF进行分区，那么MQT的设计就应该考虑是否要在各个数据库分区上复制MQT。

When there are no dependent materialized query tables ( MQT ), the system initiates the second phase after the first phase ( ALTER TABLE DETACH PARTITION ) commits .

当不存在依赖的物化查询表（MQT）时，系统在完成第一阶段（ALTERTABLEDETACHPARTITION）的提交后，启动第二阶段。