To use audits in the exchange module

The audit server logs all database actions that change the contents of a table in so-called audit files. These audit files can be used by the Exchange module. Audit files are useful in a multisite environment because the databases on all sites must have identical data. They can also be used in data conversions.

Only the updates in a specific period are exchanged, leading to an improvement in performance. Specify this period in the Export Data (Non-Regular) (daxch0233m000), Export Data (on a Regular Basis) (daxch0234m000) sessions. Changes like insert, update and delete are processed and written into the ASCII files. Actions like drop, clear and create tables are ignored.

Audit control data is added to the resulting ASCII file, consisting of a batchline-id, transaction-id, sequence-id and an indicator. The control data is added at the beginning of each line and is formatted like other data fields like the enclosing and separator characters.

An update writes two lines to the ASCII file. One line contains the keyfields and old values of the updated fields. The other line contains the new values of the keyfields and updated fields, even if a keyfield does not change.

The batchline-id is used for recognition when processing the ASCII files. The transaction- and sequence-id are used to make sure that the transactions are replayed in the same order as on the exporting site. The indicator defines the type of action that is executed on the table. Use the letter I for inserting, the letter D for deleting, U for updating with old values and the letter N for updating with new values.

Select the Based on Audit check box in the Exchange Schemes (daxch0101s000) session to enable this functionality.

To be sure that all changes made in the database are audited, a transaction notification is created in the database for each database transaction being audited. The transaction notification is inserted within the user transaction, and used by Exchange to collect the audit data. This way we are always sure that all changes are processed.

When exchanging based on audit it is important that the sequence in which the database actions are imported is the same as the sequence in which those database actions were executed on the original database by the end users. the Exchange module based on audit guarantees that the sequence of the transactions and the sequence of the database actions within each transaction are preserved. This is also the case for transactions in which multiple tables are involved.

The batchline-ids have to be identical on the export and import sites. Do not use conditions for updates that integrate two fields into one field. The audit server only logs keyfields and changed fields, therefore if only one field changes the other value will not be present in the ASCII-field.

Be careful when using conditions in the import part of exchange models that are used for auditing. They can create unsolvable problems. For example, a condition that integrates two fields into one field cannot be used for updates. The audit server only logs keyfields and changed fields, therefore if only one field has changed, the other value will not be present in the ASCII field.