DBTG Update Facility : DBMS

DBTG Update Facility -

DBTG mechanisms are available to update information in the
database.



1. To create a new record of type <record type>

-> insert the appropriate values in the corresponding
<record type> template

-> add this new record to the database by executing
           
                          store <record type>

-> Can create and add new records only one at a time





2. To modify an existing record of type <record type>

-> find that record in the database

-> get that record into memory

-> change the desired fields in the template of <record type>

-> reflect the changes to the record to which the currency point of
<record type> points by executing

                      modify <record type>






3. a) To delete an existing record of type <record type>

-> make the currency pointer of that type point to the record in the
database to be deleted

-> delete that record by executing

                          erase <record type>




b)  Delete an entire set occurrence by finding the owner of the set
and executing

                           erase all <record type>

-> Deletes the owner of the set, as well as all the set’s members.

-> If a member of the set is an owner of another set, the members of that second set also will be deleted.

-> erase all is recursive.