Use Delta to pass a packet of change log data from the client dataset to a provider. Delta contains only information about those records inserted, modified, or deleted through the client. 

When the client dataset is linked to a provider, Delta is passed as an argument to the ApplyUpdates and Reconcile methods, which use the information in the change log to update the database. On return from successful application of updates, Delta is cleared. If update errors occur, the value of Delta after applying updates depends on the error tolerance allowed by the client dataset. This value is

• All change log data when the maximum number of tolerated errors is encountered and all changes are rolled back.
• Only those changes that could not be applied when fewer errors occurred than the maximum specified as a tolerance level.

In file-based applications, Delta is cleared when the changes are merged into the Data property using the MergeChangeLog method. 

ApplyUpdates 

Data 

MergeChangeLog 

Reconcile 

AS_ApplyUpdates 

Applying Updates 

Editing Data