Managing persistent objects with object services IN SAP

There is a way to avoid building a fully object-oriented program while still working with non-object-oriented relational database. The object services layer now provides a persistence framework that closes the object-relational gap. You no longer need to write SQL code as objects are transparently loaded from the database when needed. You must create a persistent class.

Choose transaction SE24 and create a persistent class; this class must be protected.

In the class builder, a new button is added in the main toolbar - "Persistence" - press it :

in the next screen, you just have to map which fields you need in your persistent class

After having saved the previous screen, you will notice that the system creates a set/get method for each field that you selected.

Activate the whole class. Now that we have a persistent object to access the database table SFLIGHT, we must access it in a program. Here is a small example to read/write data into SFLIGHT using persistent objects.

REPORT zdany_sflight_persistent.

   DATA : l_flight       TYPE REF TO zcl_dany_sflight,

          l_flight_agent TYPE REF TO zca_dany_sflight,

          l_seatsfree    TYPE i,

          l_seatsocc     TYPE i.

* Reference to the class agent, ALWAYS required for any operation

   l_flight_agent = zca_dany_sflight=>agent.

   TRY.

*We read a record from SFLIGHT using a unique key

      l_flight = l_flight_agent->get_persistent(

          i_carrid = 'LH'

          i_connid = '0400'

          i_fldate = '20031030' ).

*We read a specific field

      l_seatsfree = l_flight->get_seatsmax( ) - l_flight->get_seatsocc( ).

      IF l_seatsfree > 0.

         l_seatsocc = l_flight->get_seatsocc( ) + 1.

* We write back a specific field into the DB

         l_flight->set_seatsocc( l_seatsocc ).

      ENDIF.

   ENDTRY.

 COMMIT WORK.

There are lots of other methods and techniques that you can use in persistent classes.

Contact Dany Charbonneau for more info.

There is a way to avoid building a fully object-oriented program while still working with non-object-oriented relational database. The object services layer now provides a persistence framework that closes the object-relational gap. You no longer need to write SQL code as objects are transparently loaded from the database when needed. You must create a persistent class.

Choose transaction SE24 and create a persistent class; this class must be protected.

In the class builder, a new button is added in the main toolbar - "Persistence" - press it :

in the next screen, you just have to map which fields you need in your persistent class

After having saved the previous screen, you will notice that the system creates a set/get method for each field that you selected.

Activate the whole class. Now that we have a persistent object to access the database table SFLIGHT, we must access it in a program. Here is a small example to read/write data into SFLIGHT using persistent objects.

REPORT zdany_sflight_persistent.

   DATA : l_flight       TYPE REF TO zcl_dany_sflight,

          l_flight_agent TYPE REF TO zca_dany_sflight,

          l_seatsfree    TYPE i,

          l_seatsocc     TYPE i.

* Reference to the class agent, ALWAYS required for any operation

   l_flight_agent = zca_dany_sflight=>agent.

   TRY.

*We read a record from SFLIGHT using a unique key

      l_flight = l_flight_agent->get_persistent(

          i_carrid = 'LH'

          i_connid = '0400'

          i_fldate = '20031030' ).

*We read a specific field

      l_seatsfree = l_flight->get_seatsmax( ) - l_flight->get_seatsocc( ).

      IF l_seatsfree > 0.

         l_seatsocc = l_flight->get_seatsocc( ) + 1.

* We write back a specific field into the DB

         l_flight->set_seatsocc( l_seatsocc ).

      ENDIF.

   ENDTRY.

 COMMIT WORK.

There are lots of other methods and techniques that you can use in persistent classes.

Contact Dany Charbonneau for more info.