SaveEdit is intiated when a component is saved.It is used to validate the consistency of the data in the component fields.It is used when more than one component field is to be validated.
Saveprechange is intiated before the component is updated in the database. Workflow: It executes immediately after Saveprechange event and before the database updates preceeds the Savepostchange event.
SavePostchange is intiated after the component is updated in the database.After the updation is done sucessfully it automatically issues commit statement.