CREATE VIEW parcel AS 
SELECT gdo gid,number,geometry, 
itt feature id, 
itt status, Lt current revset id, 
itt version,ltt commit revset id, 
itt retire revset id,ltt unique: id 
FROM parcel base; r 
CREATE VIEW parcel hist AS 
SELECT gdo gid, number, geometry, 
itt feature id, 
Itt status,ltt current revset id, 
itt yversion,itt commit revset id, 
itt retire revset id,ltt unique id, 
vht.workspace workspace, lt.version, 
nvl(.)- user name, 
decode(.) type of change, 
lt.createTime, lt.retireTime 
FROM parcel lt it, 
all version hview vht 
where lt.version - vht.version 
and 
In additonal to the views specified above, there is an additonal 
set of views generated for the  version-enabled table: 
parcel lock, parcel diff, parcel mods, etc, and 
set of metadata views maintained by DBMS. These views hold 
information about version-enabled tables, workspaces, 
savepoints, users, privileges, locks, and conflicts, etc. 
Locking management is implemented at workspace level, using 
shared locks (Section 3.3). When deleting or updating a row 
shared lock is automaticly established on the previous version 
of rows (visible to all workspaces). When updating or inserting, 
new version of rows is visible only to workspace in which they 
were created. All users in the same workspace have access to 
these rows. 
Temporal query at DBMS level involves the execution of 
GoToDate procedure (which goes to a point at specified date 
and time in the current workspace), followed by SQL query on 
history view. In the following example, user wants to see the 
parcel 1490/1 as of April 6th, 2002: 
EXECUTE dbms wm.GCoToDate('06-APR-2002'»; 
SELECT gdo gid, geometry 
FROM parcel hist 
WHERE number = ‘1490/1’; 
4.2 Temporal and Long Transaction Operations in GIS 
Cadastral temporal GIS introduces a new type of feature class, 
the secured feature class. A secured feature class is essentially a 
database table, visible to GIS desktop software through the 
Oracle Object LTT GDO data server, that has been version 
enabled and placed under Workspace manager’s control. Once 
secured, the data in the table or feature class can only be edited 
or updated through a revision set (a revision set is the term 
analogous to Workspace). Once secured, no edits of any kind 
are allowed outside a revision set (Intergraph Inc., 2003). 
To provide a secure multi-user data maintenance and editing 
environment, feature instances can be locked for use by a 
specific revision set. Once locked by a specific revision set, a 
feature is still visible to other users and revision sets, but it 
cannot be edited, modified, or deleted by any revision set other 
than the revision set that owns the lock on the feature instance. 
110 
The following figure summarizes, at a high level, the workflows 
available in temporal GIS for cadastre: 
— {Commit Al Zeis | 
EXE d 
—p.| Commit Selected Objects 
  
  
  
  
  
  
Lock (Extract) 
  
  
  
  
> View Different Revision Sets. | — ses 
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3 
> View Historical Data <— 
Temporal Queries ve 
Figure 4.3. The possible workflows in temporal GIS 
  
The following operations: 
Managing Revision Sets 
* Committing Changes 
* Discarding Changes 
* Locking Features 
* Querying Locked Features 
* Querying Modified Features 
* Applying Temporal Filters 
* Performing Temporal Queries 
can be accessed from the standard GIS desktop software. 
Regarding temporal capabilities, the last two operations are of 
interest: 
Applying Temporal Filters lets user to set the map window to 
show a view of the data as they existed at particular date and 
time in the past. However, historical data must be present in the 
data warehouse for this view mode to be used successfully. 
Display Temporal Query lets user issue a temporal query on 
secured feature classes, display the results overlaid with any 
other data in map window, and/or display the results in a data 
window (Fig 4.4). This command displays the query results in a 
view containing active revision set edits. 
      
  
ÍBROJ KC - 1490/1 
| 
   
  
  
  
  
  
Figure 4.4. An example of temporal query 
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