![]() Otherwise, TimeXtender cannot match the records in the source with the records in the data warehouse to calculate what records to delete. Delete Handling Requires Matching Primary KeysĪs stated above, if you enable delete handling, the primary key defined in the data warehouse must match the key defined in the ODX. The setting for delete handling on tables in the data warehouse applies to delete handling when data is loaded into the data warehouse. Note: This relates to the delete handling setting in the ODX for data extraction from data sources to ODX data storage. ![]() If you do not, a comparatively small Customers table can, for instance, prevent the incremental load of a much larger Invoices table. This means that it can make sense to enable delete handling on the ODX even on tables where records are never deleted. Otherwise, the tables without delete handling enabled will be full-loaded. If you map multiple incrementally loaded tables from the ODX into the same table in the data warehouse, they should all have the same setting for delete handling. TIMEXTENDER HISTORY LOAD FULLDelete Handling Triggers Full Load for Tables without Delete Handling Enabled Since the schema has changed, the new data structure no longer matches the old data. When a new column is added to the table, or a data type is changed, in the source, it will trigger a full load of the table. Incremental load, then, is simply transferring all batches with a higher batch number than the latest batch transferred to the data warehouse. When data is transferred to the data warehouse, the system keeps track of which batches are transferred. ![]() The basic logic behind the automation is as follows: The ODX stamps each load from the data source with a batch number. On the ODX source table, always set a primary key and enabled delete handling if possible. Warning: If the ODX table does not have a primary key and/or delete handling enabled, delete handling will work, but it will be very slow. Expand the field in the tree and note if the mapping icon has a key like this:.To see if a field is part of the primary key in the ODX This requires the primary key defined in the data warehouse to match the key defined in the ODX when you have delete handling enabled. TimeXtender uses the primary key to tell what records have been deleted in the source. The value of the system field "IsTombstone" can be used to tell deleted rows from valid rows. Use soft deletes: Records are marked as deleted in the data warehouse when they are deleted in the source. ![]()
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