Understanding data model updates

As PolicyCenter starts, it compares system metadata (the description of the objects and tables in the config directory) to the database to see if they match. For example, if PolicyCenter contains a new object extension added after the last server start, the database and metadata do not match. If these two do not match, PolicyCenter attempts to update the database to match the metadata. This type of update to the data model is different than a product version upgrade, which includes more extensive changes to the database.

The update process calculates current checksums for all the XML files in the data model. It then compares them with historical checksums stored in the SystemParameter entity. If the values differ, then PolicyCenter updates the database to match the metadata. As the last step in the update, PolicyCenter updates the SystemParameter entity with the current checksums.

If during the update PolicyCenter creates a new table, then it also generates a unique index for the table. The TableRegistry entity stores this information. In this way, PolicyCenter guarantees uniqueness.

Before completing the startup process, PolicyCenter again verifies the data model against the physical database. If, for some reason, the model and database disagree, PolicyCenter writes warnings to the log and, if possible, suggests corrective actions. Take the corrective action if prompted to do so.

Note: If, for any reason, there is an interruption to the server during a database update, the server resumes the update upon restart. PolicyCenter accomplishes this by storing the steps in the database and marking them completed as part of the same database transaction that applies a change. This only applies to data model updates and does not apply to product version upgrades.

Run a schema verification report

Procedure

  1. Ensure that PolicyCenter is running.
  2. Open a command prompt and navigate to the following location in the PolicyCenter installation directory:
    • admin/bin
  3. Enter the following command to generate a database schema verification report.
    • system_tools -password password -verifydbschema

    The PolicyCenter administration command prompt tools all require that you enter the password of an administrative user for the tool to work. The use of a user name is optional.