AVEVA™ Engineering

Data Integrity Checking

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The Data Integrity Checker known as DICE checks the internal structure of a database. The main checks are:

Is the complete data hierarchy intact? For example, do all lists contain all of the members that they should contain?
Are all element names correctly stored and accessible?
Are references to other databases valid? If not, a warning will be output. The most likely cause is a deleted database.

Note:
The user may find it useful to read Database Management System, before they read this chapter. DICE checks the internal structure of a database.

If the answer to any of these questions is no, a message will be output, either to your screen or to a named ASCII file in your working directory.

DICE also tells the user how many elements are stored.

The most probable causes of database corruption are:

An error in the network, resulting in loss or non-arrival of data.
An error on copying databases. In particular, this can lead to truncated databases.
Insufficient disk space or storage quota, so that the project area fills up while a database is being updated.
Deletion of a Database (DB) which is referenced from another DB.
Reconfiguration of a DB without a corresponding update of all DBs which have references pointing into it.
An undetected fault in the AVEVA base products Database Management software (refer to Database Management System).

It is important that any corruption which does occur is detected as quickly as possible, so that the System Administrator can replace the faulty database by a backup copy. For this reason, DICE is designed to operate as fast as possible, using relatively little computer resource, so that it is economic and practical to check the whole of the project database on a regular basis, and not just when an immediate need arises, such as after a computer failure. It is recommended that DICE checks should be run frequently; for example, before a daily backup is taken. DICE should be run at least once a week.