Large database tables can easily contain a million, even hundreds of millions of rows of data. Database administrators and others charged with maintaining such large datasets are always concerned about execution time for ETL (Extract, Transform, and Load) operations, updates, and other SQL queries. To make these operations more efficient, some — but not all — database vendors implemented a SQL merge statement to insert or update rows of an existing table as a single bulk-insert statement rather than requiring individual statements for each row.
Altova MapForce automatically supports SQL merge when it is available for the target database. Let’s look at an example.