RDBMS Cursor Dataset Transactions and Lockouts

Transactions

Database transactions can be used with overlays created using the database cursor datasets where the overlay has a status of editable (this will mean it is in dynamic mode).

Transactions allow users to edit the data in the overlay without others users being able to view the changes, until the current user decides to make the edits permanent.

Transaction capabilities are available for all the RDBMS cursor datasets (Oracle, Microsoft SQLServer and PostGIS). To start a transaction right-click on the database overlay in the Maps Control Bar and select Dataset > Properties...

The Cursor Dataset Details dialog will be displayed:

Lockouts

Other users who are connected to the same data source will be locked out when an item is edited during a database transaction. Users will be locked out until a Commit or Rollback are issued against the original transaction.

Whilst locked out no function in Cadcorp SIS Desktop 9.1 will be available.

Before starting a transaction you should should confirm your intended action with the GIS Manager who will be in a position to know whether the map area being edited is due to be edited by any other user.

Cadcorp recommend the following points are observed:

  • Users should not leave a transaction open for longer than necessary.
  • Users do not start a transaction and then leave their desk.
  • Database administrators should monitor the database for locked sessions.
  • GIS Managers should try to ensure that the same map features are not being modified concurrently.

For example:

If user A has started a transaction and has edited feature 1 and user B selects the same feature in another session. Cadcorp SIS Desktop 9.1 allows the feature to be selected but if an attempt is made to edit the feature Cadcorp SIS Desktop 9.1 will appear to hang. The Cadcorp SIS Desktop 9.1 session will hang until user A either commits or rolls back the transaction. This is default database behaviour and similar behaviour can be reproduced using Oracle and SQL Plus.