16
Metadata Change Management

Oracle9i Warehouse Builder enables metadata change management and version management through snapshots. You can use metadata snapshots for backup, version management, compare, and restore purposes.

This section contains the following topics:

• About Metadata Snapshots

• Snapshot Types

• Creating Snapshots

• Updating Snapshots

• Metadata Change Management Window

• Compare Snapshots

• Restore Snapshots

• Using Metadata Snapshots

• Snapshot Usage Suggestions

This section describes the metadata change management feature using the Warehouse Builder graphical user interface. For instructions on the commands and arguments to use when creating and managing snapshots using OMB Plus, refer to the Oracle9i Warehouse Builder Scripting Reference.

About Metadata Snapshots

Unlike an MDL export, which results in an .mdl file stored separately in your file system, a snapshot is stored as an object in the database. You can create snapshots for all first class objects (objects that you can access from the navigation tree). For a classification of Warehouse Builder objects, refer to "Object Ownership Tree".

A snapshot is related to the object it describes in the repository. It contains all the information about its objects and the relationships for the object. Because collections contain shortcuts to actual objects, a snapshot of a collection can be a snapshot of all the actual objects to which the shortcuts point.

If you take a snapshot of a parent object that includes child objects, and a child object changes, a snapshot comparison can show the parent object as having changed. For instance, if you create a Cascade snapshot of a project, all the modules in that project are its children. If any of the modules change, a comparison of the snapshot to the repository will show the project to have changed.

While an object can only have one current definition in the repository, it can have multiple snapshots that describe it at various points in time.

Note: When you take a snapshot of a collection, it is not a snapshot of the shortcuts in the collection but a snapshot of the actual objects. If you restore objects from this snapshot, you will restore the collection and the actual objects. Thus, when you restore a collection, you must first deselect the objects to be restored if you want to alter only the collection and not the actual objects.

Snapshots and Deleting Objects

When you delete an object from the Warehouse Builder navigation tree, a Delete Confirmation dialog displays. If you check the box indicating that you want to put this object in the recycle bin and click OK, Warehouse Builder displays a Snapshot Action dialog indicating that it is taking a snapshot of the object you are deleting.

Snapshot Types

Warehouse Builder enables you to take Full and Signature snapshots as well as Cascade and No Cascade snapshots.

Full and Signature Snapshots

This category determines the use of the snapshot:

• Full snapshot: Contains a complete set of metadata for the selected component at the time of capture. Full snapshots take longer to create and require more storage space than Signature snapshots, but provide complete metadata that you can use to restore your repository to previous history points. You can also export Full snapshots like any other repository object.

• Signature snapshot: Capture the object's signature. A signature contains enough information about the selected metadata component to detect changes when compared with another snapshot and compute the delta. Signature snapshots provide quick snapshot creation, but can only be used for comparison and information purposes. A comparison report of two snapshots identifies new, missing, and changed objects. Signature snapshots cannot be exported and imported.

If space becomes a concern, you can convert Full snapshots that you no longer need to keep for restore purposes to Signature snapshots, which consume less space. Conversion preserves the snapshot history and results in significant space savings in your repository. Currently, Warehouse Builder only enables you to perform conversions using scripting.

Note: Converting a Full snapshot to a Signature snapshot means that you can no longer use that snapshot for restore purposes.

Cascade and No Cascade Snapshots

Cascading determines the objects contained in the snapshot.

• No Cascade snapshot: Includes only the definition of the object itself, even if the object is a container object (such as a project or module) that contains child objects. For instance, if you take a No Cascade snapshot of a Warehouse Module that contains tables, your snapshot will include the definition of Module A only.

• Cascade snapshot: Includes the expanded content of the object. If you take a Cascade snapshot of Warehouse Module A, which contains two tables, your snapshot will include the definition of Module A and the definition of both tables.

Snapshot Combinations

The two categories are not mutually exclusive. Table 16-1 describes the outcomes for a snapshot of a parent object taken at various combinations.

Table 16-1 Snapshot Type Combinations  

Snapshot Type	Results of a Snapshot of Module A, which contains two tables: Table1 and Table2
Signature, Cascade Snapshot	This type of snapshot includes information about Module A, Table1, and Table2. This information cannot be used to restore those three objects; it can only be used for comparison purposes.
Full, Cascade Snapshot	This type of snapshot includes the definition of Module A, Table1, and Table2. This snapshot can be used to restore any of these three objects, or it can be used for comparison purposes only.
Signature, No Cascade Snapshot	This type of snapshot includes information about Module A only. This information cannot be used to restore Module A; it can only be used for comparison purposes. If Table1 or Table2 has changed, the comparison does not show that Module A has changed.
Full, No Cascade Snapshot	This type of snapshot includes the definition of Module A only. This snapshot can be used to restore or compare Module A, but not its children objects. If Table1 or Table2 has changed but if Module A has otherwise remained the same, the comparison does not show that Module A has changed.

Creating Snapshots

Metadata change management enables you to take snapshots that capture the content of your metadata repository, or specific objects in your repository, at a given point in time. You can use a snapshot to detect and report changes in your metadata.

Note: When you take a snapshot of a collection, it is not a snapshot of the shortcuts in the collection but a snapshot of the actual objects. If you restore objects from this snapshot, you will restore the collection and the actual objects. Thus, when you restore a collection, you must first deselect the objects to be restored if you want to alter only the collection and not the actual objects.

To create a snapshot in Warehouse Builder:

1. From the Warehouse Builder navigation tree, multi-select the components you want to include in the snapshot. For example, you can select tables, mappings, dimensions from an Oracle warehouse module.

2. Right-click the multi-selected components and select Create Snapshot from the pop-up menu.

   The Create Snapshot Welcome page displays.

3. Click Next.

   The Create Snapshot Name page displays.

4. Provide the following information:

   Name: Type a name up to 30 characters for the new snapshot.

   Type: Indicate the type for the snapshot, Full or Signature. For more information on snapshot types, see "Snapshot Types".

   Description: Type a description up to 2000 characters for the new snapshot.

5. Click Next.

   The Create Snapshot Components page displays.

   This page contains three columns:

   Object: Lists the Warehouse Builder components that you want to include in your snapshot.

   Type: Indicates the type of the Warehouse Builder component. For example, warehouse module, table, dimension, mapping, or view.

   Cascade: This option enables you to select how an object is included in the snapshot. When you choose to cascade an object, you choose to include all child components of that object in the snapshot. For example, when you cascade an Oracle target module, you choose to include all the tables, dimensions, cubes, and other objects contained in that module. This option only applies to folder-level objects, such as modules, projects, or collections.

6. Select the Cascade options for each component in the snapshot and click Next.

   The Create Snapshot Dependency page displays.

   This page enables you to select dependees for the objects in your snapshot. For example, a table with a foreign key is dependent on the table containing the referenced key. You can select 1 as the depth of dependency if you want to include the table containing the unique key in the snapshot. The maximum depth you can indicate is 100.

7. Optionally, click Preview to view the list of dependees for the depth you indicate.

   The Dependency Preview dialog enables you to preview the dependees that would be included in your snapshot. The list of dependees is based on the depth level you indicate on the Dependency page. For example, if you choose to include a mapping with a table and indicate a depth of 1, this dialog shows you the table contained in that mapping. If this table contains a foreign key and you indicate a depth of 2, this dialog lists the associated table containing the unique key.

8. Click Next.

   The Create Snapshot Finish page displays.

9. Review the choices you made in this wizard to create a new snapshot. Click Back to make changes. Or click Finish to create the snapshot.

   The snapshots you create are displayed in the Metadata Change Management window.

Updating Snapshots

After you create a snapshot, you can update it by adding more components to it. This section shows you how to update an existing snapshot.

To update an existing snapshot:

1. From the Warehouse Builder navigation tree, select the components you want to add to the snapshot. For example, you can select tables, mappings, dimensions from an Oracle warehouse module.

2. Right-click the selected components and select Add to Snapshot from the pop-up menu.

   The Add to Snapshot Welcome page displays.

3. Click Next.

   The Add to Snapshot page displays.

4. From the drop-down field, select an existing snapshot that you want to update and click Next.

   The Add to Snapshot Components page displays. This page contains three columns:

   Object: Lists the Warehouse Builder components that you want to add to your snapshot.

   Type: Indicates the type of the Warehouse Builder object. For example, warehouse module, table, dimension, mapping, or view.

   Cascade: This option enables you to select how an object is included in the snapshot. When you choose to cascade an object, you choose to include all child components of that object in the snapshot. For example, when you cascade a module, you choose to include all the tables, dimensions, cubes, and other objects contained in that module. This option only applies to folder-level objects, such as modules or projects.

5. Select the cascade options for the components you want to add and click Next.

   The Add to Snapshot Finish page displays.

6. Review the choices you specified for the snapshot. To make changes, click Back. Or click Finish to update the snapshot.

   You can view the updated snapshot in the Metadata Change Management window.

Metadata Change Management Window

Warehouse Builder enables you to manage your snapshots from the Metadata Change Management Window. To open this window, select Project then Change Manager from the Warehouse Builder console. Figure 16-1 shows the Metadata Change Management window.

Figure 16-1 Metadata Change Management Window

Text description of the illustration mcmconso.gif

This window contains two columns. The column on the left side displays the snapshots available in your repository, the date and time they were created, their owners, and their type. You can sort the list of snapshots by any of these columns by clicking on the column header.

The right side column contains two tabs: General and Components. The General tab displays name, type, and description of the selected snapshot. The Components tab displays all the objects contained in the selected snapshot in a navigation tree format. The root of this tree depends on the components contained in that snapshot. For example, if the highest level object in the snapshot is a warehouse module, then that is the root. If the snapshot contains an entire project, then the project is the root. If a snapshot only contains three tables, then those tables become the roots of the tree.

You can perform the following activities from the Metadata Change Management window:

• "Compare Snapshots"

• "Restore Snapshots"

• "Restore Snapshots"

• "Delete Snapshots"

Compare Snapshots

Warehouse Builder enables you to compare two snapshots or a snapshot with a current repository object by using Universal Object Identifiers (UOIDs) as the basis for all comparisons.

To compare two snapshots:

1. Use one of following methods:

   From the Metadata Change Management window, select Snapshot then Compare.

   Or from the list of snapshots displayed in the Metadata Change Management window, multi-select the two snapshots you want to compare, right-click the snapshots, and select Compare.

   The Compare Two Snapshot dialog displays as shown in Figure 16-2. If you already selected the two snapshots you want to compare, they will be pre-selected in the columns of this dialog.

Figure 16-2 Compare Two Snapshots Dialog

Text description of the illustration twosnaps.gif

2. Select the snapshots you want to compare from the Choose Snapshot 1 and Choose Snapshot 2 columns and then click Compare.

   Warehouse Builder displays the comparison results in the Snapshot Comparison dialog. For more information, see "Snapshot Comparison Dialog".

To compare a current repository object with a snapshot component:

1. Select the object you want to compare from the Warehouse Builder navigation tree.

2. Right-click the object and select Compare With Snapshot.

   The Choose Snapshot dialog displays. This dialog lists all the snapshots containing versions of that object.

3. Select the snapshot to which you want to compare the current repository object and click OK.

   The Snapshot Comparison dialog displays the comparison results. For more information, see "Snapshot Comparison Dialog". If the repository object has not changed, then Warehouse Builder displays a message stating that there is no change.

Snapshot Comparison Dialog

When you compare two snapshots or when you compare a snapshot component with a repository object, the results display in the Snapshot Comparison dialog.

Note: When two snapshots are identical, Warehouse Builder displays a message that the two snapshots are identical. In this case, you will not see the Snapshot Comparison dialog.

The View filter option at the top enables you to view only the changed objects. You can also select All Objects to display all objects in the snapshot, whether they are changed or not.

The Snapshot Comparison dialog contains two columns. The left side column displays the comparison results in a navigation tree format. The tree icons indicate the status of the snapshot components as shown in Table 16-2.

Table 16-2 Snapshot Comparison Icons

Icon	Status
Text description of the illustration mcm1.gif	Both Snapshot 1 and Snapshot 2 contain the component. There is no change.
Text description of the illustration mcm2.gif	The component only exists in Snapshot 1.
Text description of the illustration mcm3.gif	The component only exists in Snapshot 2.
Text description of the illustration mcm4.gif	The object exists in both snapshots but it has changed.

The right side column contains three tabs: General, Properties, and Links. These tabs display the following information:

General: Provides an overview of the comparison results. Select an object name from the navigation tree in the left column to view a summary of its physical name, business name, and type. This column also indicates whether there are any changes in the object properties, associated child components, or links.

Properties: Shows whether the properties of an object have changed or whether the object exists in both snapshots or only one of them.

Links: Shows whether there are changes to any links or associations for the object. The icons under the Difference field indicate the status of the object as shown in Table 16-2.

To save the comparison results as an XML file, click Save As. Or click Close to close the dialog.

Considerations

When you compare snapshots, Warehouse Builder uses the Unique Object Identifier (UOID) for each object to perform the match. If you delete an object and recreate it with same metadata, the object now has a different UOID, although it looks similar to the deleted object. When you compare this object to its previous version, the results will show all the metadata as changed because you recreated the object again. Not only the changed metadata but the unchanged metadata also displays in the comparison results.

Because Warehouse Builder uses UOID to match nodes, if objects are deleted and recreated during MDL import or Intelligence Object derivation, the results will be different. This is true even if you trigger IGNORE UOID = TRUE during MDL Import.

Restore Snapshots

When you restore a snapshot, you replace the current definition of the object in the repository with the snapshot image of that object. When restoring from full, cascade snapshots of projects, collections, or folders, you can select which child objects you want to restore. You can restore the complete snapshot, or only a part of it by selecting specific child objects.

To restore a snapshot:

1. Open the Metadata Change Management window and select the snapshot you want to restore.

2. Right-click the snapshot and select Restore from the pop-up menu. Or from the Snapshot menu, select Restore.

   If you have uncommitted work, you will be asked to commit first before restoring a snapshot.

   Then the Restore Snapshot dialog displays as shown in Figure 16-3.

Figure 16-3 Restore Snapshot Dialog

Text description of the illustration restore.gif

This dialog enables you to select the components to restore from a snapshot. By default, Warehouse Builder restores all components if you click Restore. You can also restore only a part of the snapshot by selecting specific child objects.

When you restore folders, all its child objects are also restored. For example, if you choose to restore a warehouse module, all the objects contained in that module are also automatically restored. To restore only selected objects within this warehouse module, you must first uncheck the warehouse module or any other folder and then selectively restore the objects within that folder.

The Restore dialog contains the following columns and options:

Component: Lists the Warehouse Builder components included in the snapshot.

Type: Indicates the type of the Warehouse Builder object. For example, warehouse module, table, dimension, mapping, or view.

Select: This is the column you check to indicate whether you want to restore the component.

Cascade Up: This option controls the restore when the parent of a component no longer exists in the repository. For example, you are restoring a table T1 originally located under MY_WH module under project MY_PROJECT. By checking Cascade Up, the system creates a dummy MY_PROJECT and MY_WH containing T1. If you do not check Cascade Up, the system will not be able to locate the parent folders for this table and the restore will fail.

Click Restore to restore the selected snapshot objects to the repository. Warehouse Builder warns you that all currently open editors will be closed after a successful restore. Click Yes to continue and complete the restore.

Delete Snapshots

You can delete snapshots or components within a snapshot from the Metadata Change Management window.

To delete a snapshot:

1. Open the Metadata Change Management window and select the snapshot you want to delete.

2. Right-click the snapshot and select Delete from the pop-up menu. Or from the Snapshot menu, select Delete.

   Warehouse Builder displays a delete confirmation dialog.

3. Click Yes to delete the selected snapshot from the repository.

To delete components in a snapshot:

1. Open the Metadata Change Management window and select the snapshot from which you want to delete components.

2. From the right-side column of the Metadata Change Management window, select the Components tab.

   Warehouse Builder displays the components of the snapshot on the right-side column.

3. Right-click the component you want to delete and select Delete from the pop-up menu. Or from the Snapshot menu, select Delete.

   Warehouse Builder displays a delete confirmation dialog.

4. Click Yes to delete the selected component from the snapshot.

Using Metadata Snapshots

This section explains snapshot usage concepts using OMB Plus. For instructions on the commands and arguments for creating and managing snapshots using OMB Plus, refer to the Oracle9i Warehouse Builder Scripting Reference.

History Management

History management includes creating, deleting, restoring, and altering snapshots.

Creating Snapshots

Use the following syntax to create a snapshot:

OMBCREATE SNAPSHOT 'SNAPSHOTNAME' SET PROPERTIES (DESCRIPTION,SNAPSHOTTYPE) VALUES (Your description value, 'FULL')

ADD FIRST_CLASS_OBJECT_TYPE FULLY_QUALIFIED_FIRST_CLASS_OBJECT_NAME ...

Example:

OMBCREATE SNAPSHOT S1 SET PROPERTIES (DESCRIPTION, SNAPSHOTTYPE) VALUES ('Sample Snapshot', Y ,Y)

ADD TABLE 'MY_PROJECT/WH/EMP'

ADD TABLE 'MY_PROJECT/WH/DEPT'

ADD DIMENSION 'MY_PROJECT/WH/DIM1'

ADD MAPPING 'AnotherProject/WH1/MAP1'

Deleting Snapshots

Use the following syntax to delete a snapshot:

OMBDROP SNAPSHOT 'SNAPSHOTNAME'

Example:

OMBDROP SNAPSHOT 'SS1'

Altering Snapshots

You can alter an existing snapshot directly, thus "altering history" as you need. You can also use the ALTER command to delete a non-root snapshot (for more information about root snapshots, see "Cascade and No Cascade Snapshots").

Use the following syntax to alter a snapshot:

OMBALTER SNAPSHOT 'SNAPSHOTNAME'

( SET PROPERTIES (SNAPSHOTTYPE) VALUES ('FULL'/'SIGNATURE')

)?

( ADD FIRST_CLASS_OBJECT_TYPE RELATIVE_FIRST_CLASS_OBJECT_NAME

| DELETE FIRST_CLASS_OBJECT_TYPE RELATIVE_FIRST_CLASS_OBJECT_NAME

| MODIFY FIRST_CLASS_OBJECT_TYPE RELATIVE_FIRST_CLASS_OBJECT_NAME

)+

Example:

OMBALTER SNAPSHOT S1

ADD TABLE 'MY_PROJECT/MOD1/T1'

ADD TABLE 'MY_PROJECT/MOD1/T2'

DELETE DIMENSION 'MY_PROJECT/WH/DIM1'

This command adds two tables and removes the existing dimension from the snapshot definition.

Restoring Snapshots

Restoring a snapshot means replacing the current definition of the object in the repository with the snapshot image of that object. When restoring from full, cascade snapshots of projects, collections, or folders, you can select which child objects you want to restore. You can restore the complete snapshot, or only a part of it by selecting specific child objects.

Restoring an Entire Snapshot

Use the following syntax to restore an entire snapshot:

OMBRESTORE SNAPSHOT 'SNAPSHOTNAME'

Example:

OMBRESTORE SNAPSHOT 'SS1'

This command restores all the objects in the snapshot. If any instances fail to restore, the whole operation fails with an error message. Failure to restore means that the aggregate parent of all the objects within the snapshot does not exist in the current repository.

Restoring Selected Objects from a Snapshot

Use the following syntax to restore select objects from a snapshot:

OMBRESTORE SNAPSHOT 'SNAPSHOTNAME' FOR FIRST_CLASS_OBJECT_TYPE 'RELATIVE_FIRST_CLASS_OBJECT_NAME'

Example:

OMBRESTORE SNAPSHOT 'SS1' FOR TABLE 'MY_PROJECT/WH/EMP' MAPPING 'AnotherProject/WH1/MAP1'

This command replaces the current repository metadata definition of table EMP and mapping MAP1 with the table and mapping defined in snapshot SS1.

Orphaned Snapshots

Deleting an object that has snapshots does not delete the snapshots of that object. Deleting an object can therefore result in a snapshot being orphaned, or remaining in the repository without an object to which it belongs. If you try to restore an orphaned snapshot, Warehouse Builder produces an error message.

Use the following syntax to restore the missing parents of an orphaned snapshot:

OMBRESTORE SNAPSHOT 'SNAPSHOT_NAME' CASCADE UP

Snapshots follow Warehouse Builder's transaction mechanism, so you will not have orphaned snapshots resulting from a rollback. If you create a new object and a snapshot of it without committing, and then rollback your changes, the object and snapshot are both deleted.

Exporting and Importing Snapshots

You can export and import full snapshots only, using the OMB Plus scripting interface and the Warehouse Builder user interface. Export and import full snapshots to move them between repositories or to use them for future upgrades. Exporting a full snapshot converts it into a Metadata Loader .mdl file. Importing a full snapshot converts an .mdl file into a snapshot and stores the snapshot in the tablespace allotted for snapshot storage in your repository.

Change Management

Change management includes listing, retrieving information about, and comparing snapshots.

Listing Snapshots

You can list all available snapshots for a given repository, or you can list any snapshots associated with a specific object in the repository.

Listing All Snapshots for a Repository

Use the following syntax to list all snapshots for a repository:

OMBLIST SNAPSHOTS regexp

Example:

OMBLIST SNAPSHOTS

This command returns a list of all snapshots for the repository in question.

Listing Snapshots Associated With an Object

Use the following syntax to list existing snapshots for a specific object:

OMBLIST SNAPSHOTS FOR FIRST_CLASS_OBJECT_TYPE 'RELATIVE_FIRST_CLASS_OBJECT_NAME'

Example:

OMBLIST SNAPSHOTS FOR TABLE 'EMP'

This command lists the names of all snapshots that are associated with the current table EMP.

Retrieving Information About Snapshots

Use the following syntax to retrieve information about a snapshot:

OMBRETRIEVE SNAPSHOT 'SNAPSHOTNAME' GET

( PROPERTIES (TIMESTAMP|DESCRIPTION|SNAPSHOTTYPE)

| CONTENTS (ALL | MAPPINGS | TABLES |...)

( START WITH 'FIRST_CLASS_OBJECT_NAME')? (CASCADE | NO CASCADE)? ) )

Examples:

• OMBRETRIEVE SNAPSHOT S1 GET PROPERTIES (DESCRIPTION)

  This command returns the description for snapshot S1:

  Sample Snapshot

• OMBRETRIEVE SNAPSHOT S1 GET CONTENTS ALL

  This command returns:

  TABLE 'MY_PROJECT/WH/EMP'

  TABLE 'MY_PROJECT/WH/DEPT'

  DIMENSION 'MY_PROJECT/WH/DIM1'

  MAPPING 'AnotherProject/WH1/MAP1'

• OMBRETRIEVE SNAPSHOT S1 GET CONTENTS TABLES

  This command returns:

  TABLE 'MY_PROJECT/WH/EMP'

  TABLE 'MY_PROJECT/WH/DEPT'

Comparing Snapshots

Using the OMB Plus utility, you can compare two snapshots to each other, or a snapshot to a current repository object. Warehouse Builder uses Universal Object Identifiers (UOIDs) as the basis of all comparisons.

When comparing two snapshots or a snapshot with an object, identify one as the source and one as the target. For instance, if you are comparing a snapshot to a current module object with the intention of restoring certain properties to the object, the snapshot is your source and the object is your target.

You can select from the following comparison report filters, to report on:

• Objects that are found in the source only: This method only identifies objects that are found in the source but not in the target.

• Objects that are found in the target only: This method only identifies objects that are found in the target object but not in the source object.

• Changed objects found in both source and target: This method identifies objects that are found in both the source and target, but whose definitions differ in the two.

• Unchanged objects found in both source and target: This method identifies objects that are identical in both source and target.

• All objects: This method identifies all the objects in the target, plus objects found in the source only.

You can generate a comparison report when you compare two snapshots to each other, or a snapshot to a current repository object. A comparison report is generated in XML format, and identifies new, missing, and changed objects. You can generate snapshot comparison reports from the mcmview.bat command line utility, or from OMB Plus.

Comparing Snapshots in OMB Plus

To generate snapshot comparison reports from OMB Plus, use the prepackaged XML schema defined for the generated XML. For more information, consult the Oracle9i Warehouse Builder Scripting Reference.

Use the following syntax to compare two snapshots in OMB Plus:

OMBCOMPARE SNAPSHOT 'SRC_SNAPSHOTNAME' WITH

( SNAPSHOT 'TGT_SNAPSHOTNAME' | CURRENT )

FOR FIRST_CLASS_OBJECT_TYPE 'RELATIVE_FIRST_CLASS_OBJECT_NAME'

SHOW (ALL | CREATED | DELETED | MODIFIED | UNMODIFIED) OUTPUT TO 'XMLFILENAME'

Examples:

• OMBCOMPARE SNAPSHOT 'SS1' WITH SNAPSHOT 'SS2' FOR TABLE 'EMP' SHOW ONLY DELETED OUTPUT TO 'c:\diffresults\emp_diff.xml'

• OMBCOMPARE SNAPSHOT 'SS1' WITH CURRENT FOR TABLE 'MY_PROJECT/WH/EMP' SHOW ONLY DELETED OUTPUT TO 'c:\diffresults\emp_diff.xml'

Comparing Snapshots in the Command Line Utility MCMVIEW.BAT

A command line utility, mcmview.bat, is packaged for the purpose of generating snapshot comparison reports as well. The command line utility prepares the XML for reading and printing the report in HTML format. The utility is located in the owb/bin/win32 directory and should be executed passing the OWB compare XML filename as a parameter.

For example, the command mcmview c:\temp\tables_021111.xml results in a file named tables_021111.xml.html in the win32 directory, and the suffix .html is added to the XML file name.

Snapshot Usage Suggestions

Used in conjunction with other Warehouse Builder features, such as the MDL Metadata Import utility and impact analysis, snapshots facilitate metadata management. Snapshots are also designed to meet the unique needs of different Warehouse Builder users.

Using Snapshots in Conjunction with Other Warehouse Builder Functionality

Use snapshots in conjunction with MDL metadata import to determine the impact an import will have on the current metadata repository. Based on a repository snapshot comparison, select actions to perform metadata import at a finer grain of detail. You can use impact analysis prior to metadata import to determine the dependent objects that will be impacted by the changes you plan to accept during import. You can also use snapshots during deployment to identify the objects that need to be redeployed.

Snapshot Views for Data Warehouse Designers and Managers

Metadata snapshots vary in granularity to account for the unique needs of different Warehouse Builder users. Warehouse designers can use snapshots to capture their individual components, such as their mappings, entities, and process flows, at various points in time, whereas data warehouse managers can use snapshots to detect or preserve the history of an entire warehouse module or project. Snapshot views are accessible through OMB Plus. For more information, see the Oracle9i Warehouse Builder Scripting Reference.

The Object to Snapshot view for designers enables data warehouse designers to take snapshots of their work.

• For instance, when working on a specific mapping or entity, a developer can take a full snapshot of that entity. Later, that developer can restore the mapping to its previous state using the full snapshot.

• Or, a developer can take a signature of a specific component and later use that snapshot to identify the changes that have occurred for that component.

The Snapshot to Object view for managers enables data warehouse managers to survey metadata history.

• Managers can use this view to oversee, delete, and compare the snapshots created in the repository.

• This view enables the administrator to perform large-scale actions, such as deploying a warehouse or restoring a warehouse to a previous point in history.

• The data warehouse manager can also delete old, unnecessary snapshots in bulk using this view.

• Managers can view all the snapshots associated with a specific object in one window and can manage them through one consolidated view in the repository.

• Finally, this view also enables the data warehouse manager to upgrade snapshot storage to match a new version of Warehouse Builder software.