Changes to database records in Force.com are saved using Data Manipulation Language (DML) operations. DML operations allow you to modify records one at a time, or more efficiently in batches of multiple records. The five major DML operation types are listed next. Each is discussed in more detail later in this subsection.
Insert—Creates new records.
Update—Updates the values in existing records, identified by Force.com unique identifier (
Id) field or a custom field designated as an external identifier.
Upsert—If records ...