Article
10/01/2010

Events (DSO)

Note

This feature will be removed in the next version of Microsoft SQL Server. Do not use this feature in new development work, and modify applications that currently use this feature as soon as possible.

The only object in Decision Support Objects (DSO) that directly supports event trapping is the Database object. This object fires events for all of its child objects including shared dimensions, cubes, partitions, aggregations, and data mining models.

The following table lists the events that this object supports.

Event	Description
ReportAfter	Called whenever a processing action on an object in the database has finished executing
ReportBefore	Called before a processing action on an object in the database
ReportError	Called whenever an error occurs during a processing action
ReportProgress	Called to report the progress of an action during a processing

Processing Actions

Each event reports the status of the processing action. This processing action is represented by integer constants. The tense for each processing action depends on the event being trapped. For instance, the merge action (mdactMerge) reports that two partitions or aggregations will bemerged when trapped in the ReportBefore event. In contrast, this same action reports that two partitions or aggregations have been merged when trapped in the ReportAfter event.

The following is a list of actions that are supported by the database object events:

Action	Constant	Description
Process	mdactProcess	Indicates that the object referred to by obj has been processed.
Merge	mdactMerge	Reports that two partitions/aggregations have been merged.
Delete	mdactDelete	Indicates that an object has been deleted.
Delete Old Aggregations	mdactDeleteOldAggregations	Indicates that the existing relational OLAP (ROLAP) aggregations of a partition have been deleted.
Rebuild	mdactRebuild	Indicates that the definitions of an object have been rebuilt.
Commit	mdactCommit	Indicates that a transaction has been committed on the database.
Rollback	mdactRollback	Reports that a transaction has been rolled back on the database.
Create Indexes	mdactCreateIndexes	Indicates that indexes for a ROLAP aggregation have been created.
Create Table	mdactCreateTable	Reports that the aggregation table for the ROLAP aggregation has been created.
Insert Into	mdactInsertInto	Indicates that the aggregation table for the ROLAP partition has been populated.
Transaction	mdactTransaction	Reports that a transaction has been started, completed, or has encountered an exception.
Initialize	mdactInitialize	Indicates that the object referred to by the obj parameter has been initialized.
Create View	mdactCreateView	Reports that an aggregation view has been created for the ROLAP aggregation. This action is only valid when processing a ROLAP cube with Microsoft® SQL Server™ 2005 using indexed views.
Write Data	mdactWriteData	Data has been written to the disk.
Read Data	mdactReadData	Data has been read from the disk.
Aggregate	mdactAggregate	Aggregations are being built.
Execute SQL	mdactExecuteSQL	An SQL statement has been executed.
Now Executing SQL	mdactNowExecutingSQL	An SQL statement is executing that can be canceled.
Executing Modified SQL	mdactExecuteModifiedSQL	A modified SQL statement has been executed.
Rows Affected	mdactRowsAffected	Reports number of rows affected by an SQL statement.
Error	mdactError	Indicates that an error has occurred during processing.
Write Aggregations and Indexes	mdactWriteAggsAndIndexes	Indexes and aggregations will be written to the disk.
Write Segment	mdactWriteSegment	Segments will be written to the disk.
Data Mining Model Processed Percentage	mdactDataMiningProgress	The status of the completion of processing for a data mining model in percentage terms.

For more information about the Database object, see clsDatabase.

Tutorial - Trapping Database Events

The following tutorial demonstrates trapping processing events. In examples A through C, a Microsoft Visual Basic® project file is set up that contains all of the information needed to use the rest of the examples. Examples D through G demonstrate trapping each of the events that are available from the database object.

A. Setting up the Project File

Start Visual Basic and create a new project called Project1.
In the Project References dialog box, select the Microsoft Decision Support Objects check box.
In the Project Components dialog box, click Microsoft Windows Common Controls 6.0 (SP3).
Create a new module called Module1.
Create a new form called Form1.
Add a text box to the form called Text1.
Add a button called Command1 to the form and label it "Process".
Add another button called Command2 to the form and label it "Cancel".
Add a progress bar control named ProgressBar1.

In the form's general declarations section, add the following code:

Option Explicit

'Declare a database object with events.
Public WithEvents dsoDb As DSO.Database

'Declare some useful variables and constants.
Public gCubeMaxRows As Long
Public gbCancel As Boolean
Private Const SERVER_NAME = "LocalHost"
Private Const DATABASE_NAME = "FoodMart 2000"