Neoview Control Query Default (CQD) Reference Guide (R2.5)

10 Managing Materialized Views
This section describes these CQDs that are used for managing materialized views:
• “MV_ALLOW_SELECT_SYSTEM_ADDED_COLUMNS” (page 43)
• “MVGROUP_AUTOMATIC_CREATION” (page 43)
MV_ALLOW_SELECT_SYSTEM_ADDED_COLUMNS
Materialized view controlsCategory
When an incremental Materialized View (MV) is created, system columns are added to
support the maintenance of the MV. When this CQD is ON, system added columns can be
viewed when executing a “select *” from an MV.
Description
Displays columns added to the Materialized View by the system.‘ON’
The system added columns are not displayed.‘OFF’
The default value is ‘OFF’.
Values
When incremental MVs are created there are some columns that are automatically added
to support the maintenance of the MV. For example, when there is an AVG aggregate in
the MV, the SUM and COUNT computations are added to the MV as well, so that they can
be used to compute the average. Or, when a STDDEV(a) is specified in an MV definition
COUNT(a), SUM(a) and SUM(a*a) are automatically added.
Use this CQD:
• To see the values of these columns
• To query these values
• To check the integrity of the computed aggregate
• If an MV is created on top of such an MV, to use these system generated columns in
that MV as well.
Usage
Not applicableProduction usage
Not applicableImpact
QueryLevel
Not applicableConflicts/Synergies
Not applicableAddressing the real
problem
Neoview Release 1.0Introduced in release
Not applicableDeprecated in release
MVGROUP_AUTOMATIC_CREATION
Materialized view controlsCategory
Materialized View Groups are used to simplify the maintenance of MVs by logically
grouping related MVs together so they can be maintained at the same time. These groups
can be automatically created or dropped and MVs automatically added to or removed from
them when they are created or dropped.
Description
MV_ALLOW_SELECT_SYSTEM_ADDED_COLUMNS 43