MODIFY...TO COMBINE Statement--Merge and Update Data
For large updates, we recommend using a bulk insert (for example, COPY or vwload) to initially load the data into staging tables, and then using explicit MODIFY...TO COMBINE statements.
The syntax of the MODIFY...TO COMBINE statement is as follows:
MODIFY [schema.]tablename [[UNION ut] [EXCEPT et] ...] TO COMBINE
This statement tells the system that all tuples from except tables must be deleted from the base table, and then all tuples from union tables must be added to that table. This statement generates a new copy of the base table.
For detailed usage notes on MODIFY...TO COMBINE, see the Vector SQL Language Guide.