Steps for "Upsert" operation using Data Loader: in Salesforce

Upsert --->This operation is used for inserting new records and modifying the existing records at a time.
i.e insert + update

Note: For updating the existing records, we need Salesforce record ID(15 digits or 18 digits)

For inserting the new records, no need Salesforce record ID. Once the records inserted, salesforce
automatically generates the ID.

• Step 1 : Salesforce Settings
• Step 2 : Select the Data Object and CSV file
• Step 3 : Mapping
• Step 4 : selecting the directory