Ususally database operations fall into one of the three following groups:
- Add
A new entry is created.
- Modify
An entry is modified. Some data might have changed or some details might have been added.
- Delete
An entry is deleted. It no longer exists in a database.
To make it even simpler, the “add” operation is just a special case of the “modify” operation: It is the modification of a non-existing item.