Automator Update Existing Rows and Append New feature

I am running Automator 14.1

I have been trying to get clarification on how Automator performs the Update Existing Rows and Append New function into a database (SQL Server)

How does Automator know what records to update that are already in a database table?

Does it prompt you for specific keys to check against?

The Automator Administration documentation I have read doesn't get into specifics.

The Table Info screen includes the following settings:

 Description: Displays information about the export, such as whether filters are applied to the table or summary data, the filename and path of the output file, etc.

 Table Name: Displays the current name of the table. You can assign a new table name by entering it here.

 Existing Tables: Displays the names of the tables in that file when exporting to a file that already exists.

 When output tables exist options:

 Overwrite existing table: Overwrites the data in the existing table with the data in the export table.

 Append data to existing table: Adds the export table data to the end of the selected existing table.

 Update existing rows (OLE DB direct exports of table data only): Updates existing rows in a table.

 Update existing rows and append new (OLE DB direct exports of table data only): Updates existing rows in a table and append new rows to it.

 Skip (no output): Skips the export operation if a table of the same name already exists. This is useful for automated operations, where you may not want to overwrite a table that already exists.

NOTES

Some of these options apply only to OLE DB direct exports. In addition, if you are performing a file system output, some of these options are only accessible if you selected the Add data to file option on the File Info screen.