Delta Mode Connectors

The Delta mode is designed to simplify the application of changes to data by providing incremental modifications to the connected system, based on delta operation codes. Incremental modifications means to write only the specific values that have been changed.

Firstly, Delta mode handles all types of deltas: adds, modifies and deletes. The Delta mode requires receiving a Delta Entry to operate. Therefore when using a Connector in Delta mode, it must be combined with components that produce Delta Entries; these are Iterator Connectors with enabled Delta, Change Detection Connectors or Connector using an LDIF or DSMLv2 Parser. For example, you can synchronize two systems with the use of only two Connectors: one Change Detection Connector in the Feeds section to pick up the changes, and a second Connector in Delta mode to apply these changes to a target system.

Furthermore, Delta mode will apply the delta information at the lowest level supported by the target system itself. This is done by first checking the Connector Interface to see what level of incremental modification is supported by the data source. If you are working with an LDAP directory, then Delta mode will perform AttributeValue additions and deletes. In the context of a traditional RDBMS (JDBC), deleting and then adding a column value does not make sense, so this is handled as a value replacement for that Attribute.

Also, incremental modifications are automatically dealt by the Delta mode for those data sources that support this functionality. If the data source offers optimized calls to handle incremental modifications, and these are supported by the Connector Interface, then Delta mode will use these. On the other hand, if the connected system does not offer "intelligent" delta update mechanisms, Delta mode will simulate these as much as possible, performing pre-update lookups (like Update mode), change computations and subsequent application of the detected changes.

Note: The only Connectors that support incremental modifications are the LDAP Connectors, since LDAP directories provide this functionality.

The Delta features in IBM® Security Verify Directory Integrator are designed to facilitate synchronization solutions using not only data sources providing change detection mechanism but also, for example, flat files. The following diagram shows such a synchronization solution using Connectors in Iterator and Delta mode. The Iterator Connector reads entries from a data source. The read entries are compared to the ones saved in the Delta Store on the previous iteration. The result of the comparison is a Delta Entry assigned with delta operation codes defining the made change – add/delete/modify. Then the Delta Entry is used by the Connector in Delta mode to apply the detected changes to a destination system.

Figure 1. Synchronization AssemblyLine using Delta functionality

The result of the AssemblyLine execution is that the data contained in the data source is synchronized with the data in the destination system