Databases Reference
In-Depth Information
of changes made in that workspace up to another point in time. You can think of this
as a type of Flashback (described in
Chapter 3
) for a limited set of tables.
In addition, you can specify that a particular version of data in a workspace is valid only
for a specific time period. For instance, you could make a change to data that would be
visible to workspace users for the next 24 hours and that would then disappear. This
type of functionality has been added to the core database in Oracle Database 12
c
with
the valid time temporal feature, described in
Chapter 4
.
Workspaces have their own locking mechanisms that apply only to other workspace
users. You can exclusively lock a row of data in a workspace, but this lock prevents access
only to that row for other workspace users. The underlying data could still be accessed
or changed by users who are not part of the workspace. This additional locking makes
sense, since both locks and workspaces are meant to isolate data from changes. A work‐
space exists outside the boundaries of the standard database, so workspace locks and
standard database locks do not directly interact.
Workspace Operations
There are three basic operations that apply to workspaces:
Rollback
You can roll back changes to a workspace to return the workspace to the point in
time when the workspace was created. You can also designate savepoints, which
allow you to roll back the changes in a workspace to a subsequent point in time.
Refresh
Refreshing a workspace means bringing the data in a workspace into agreement
with the same data in the overall database. This capability could be used if you chose
to create a workspace with a snapshot of the data at the end of a day. At midnight,
you would refresh the workspace to make the workspace reflect the data from the
previous day.
Merge
A merge operation rolls changes made in a workspace into its parent workspace.
As you can imagine, both the refresh and the merge operations could end up with
conflicts between data values in the workspace and its parent. Workspace management
keeps track of conflicts on a per-table basis; you can resolve the conflicts manually.
Workspace Enhancements
Workspace Manager is tightly integrated with the Oracle Database. Oracle Database
10
g
Workspace Manager enhancements included the ability to export and import
version-enabled tables, to use SQL*Loader to bulk load data into version-enabled tables,
