一个完整的CRUD例子

1.思想
      明确的MVC模式，把所有的方法声明代码实现都写在componentcontroller里，在view里声明方法去调就可以了。

2.节点及类和方法的实现flightinfo(sflight类型):
carrid
connid
flighttab(sflight类型):
carrid
connid
fldate
planetype
seatmax
seatsocc
isreadonly:
isread(boolean)
issave(boolean)

两个内表：(通过se11定义)
zit_bookings zit_flighttab

*****************    类zcl_net310_flightmodel:   *************************************************************************

Attributes:
   ty_flights static type sflight       航班
   zit_outtab static type ty_sflight table of flights
   zit_outbook static type zit_bookings 航班订票

methods:
方法名称 参数 参数类型 说明
read_flights   i_carrid         importing type sflight-carrid        航运承运人id    读取航班信息表
       i_connid         importing type sflight-connid        航班连接id
       e_flights exporting type zit_flighttab      航班
 
read_bookings  i_carrid         importing type sflight-carrid      航运承运人id    读取某一航班的具体信息
       i_connid importing type sflight-connid      航班连接id
       i_fldate importing type sflight-fldate        航班日期
       e_bookings exporting type zit_bookings      航班订票

insert_flights i_flights importing type zit_flighttab          inter table     插入一条航班记录

delete        sel_carrid importing type sflight-carrid      航运承运人id     删除一条航班记录
       sel_connid importing type sflight-connid      航班连接id

modify_flights i_flights importing type zit_flighttab       inter table     通过内表更新航班记录

所有方法均定义成static public
***************************************************************************************************************************

方法的具体实现:
method READ_FLIGHTS.
  data i_lines type i.

  if i_carrid = '' or i_connid = ''.
    select * from sflight into table zit_outtab.
  else.
    select * from sflight into table zit_outtab where carrid = i_carrid and connid = i_connid.
  endif.

  e_flights = zit_outtab.

describe table e_flights lines i_lines.
if i_lines <= 0.
  return.
endif.
endmethod.


method READ_BOOKINGS.
select * from sbook into table zit_outbook where carrid = i_carrid and connid = i_connid and fldate = i_fldate.
*select * from sbook into table zit_outbook.
e_bookings = zit_outbook.
endmethod.


method INSERT_FLIGHTS.
insert sflight from table i_flights ACCEPTING DUPLICATE KEYS.
endmethod.


method DELETE.
delete from sflight where carrid = sel_carrid and connid = sel_connid.
endmethod.

method MODIFY_FLIGHTS.
*update，不可以改变关键字段的值，但可以改变非主关键字段的值。
*modify覆盖具有主关键字的数据条目，找不到已存在相同主关键字的条目就将新行添加到数*据库表中。
  update sflight from table i_flights.
endmethod.
3.get_user_input
method GET_USER_INPUT .
data: lr_node_flightinfo type ref to if_wd_context_node,
      lr_elem_flightinfo type ref to if_wd_context_element,
      ls_flightinfo      type        if_componentcontroller=>element_flightinfo.

* get user input
lr_node_flightinfo = wd_context->get_child_node(
   name = if_componentcontroller=>wdctx_flightinfo
).
lr_elem_flightinfo = lr_node_flightinfo->get_element( ).
lr_elem_flightinfo->get_static_attributes(
   importing
     static_attributes = es_flightinfo
).
endmethod.
4.get_flights
method GET_FLIGHTS .
data:  ls_flightinfo type sflight,
       lt_flighttab    type zit_flighttab,
       lr_node_flighttab type ref to if_wd_context_node.

* get flightinfo key from context
wd_this->get_user_input(
  importing
    es_flightinfo = ls_flightinfo
).
* get related flighttab
  CALL METHOD zcl_net310_flightmodel=>read_flights
    exporting
      i_carrid = ls_flightinfo-carrid
      i_connid = ls_flightinfo-connid
    importing
      e_flights = lt_flighttab.
*store flighttab in context
    lr_node_flighttab = wd_context->get_child_node(
      name = if_componentcontroller=>wdctx_flighttab
    ).
    lr_node_flighttab->bind_table( lt_flighttab ).
endmethod.
5.handle_from_inputview
      在inputview的outbound里定义了一个参数actiontype，这里也要定义一个相同类型的参数actiontype接收，以区别是显示还是修改，实现页面的共用。
method HANDLEFROM_INPUT_VIEW .
data lo_nd_isreadonly type ref to if_wd_context_node.
data lo_el_isreadonly type ref to if_wd_context_element.
data ls_isreadonly    type        wd_this->element_isreadonly.
DATA lo_COMPONENTCONTROLLER TYPE REF TO IG_COMPONENTCONTROLLER .
lo_COMPONENTCONTROLLER =   wd_this->get_componentcontroller_ctr( ).

  lo_componentcontroller->get_flights(
      ).

* set the isreadonly
lo_nd_isreadonly = wd_context->get_child_node(
  name = wd_this->wdctx_isreadonly
).
lo_el_isreadonly = lo_nd_isreadonly->get_element( ).
*lo_el_isreadonly->get_static_attributes(
*  importing
*    static_attributes = ls_isreadonly
*).

case actiontype.
  when 'V'.
    ls_isreadonly-isread = 'X'.
    ls_isreadonly-issave = ''.
    lo_el_isreadonly->set_static_attributes(
      exporting
        static_attributes = ls_isreadonly
    ).
  when 'U'.
    ls_isreadonly-isread = ''.
    ls_isreadonly-issave = 'X'.
    lo_el_isreadonly->set_static_attributes(
      exporting
        static_attributes = ls_isreadonly
    ).
endmethod.
6.store_data
method STORE_DATA .
data: lo_nd_flighttab type ref to if_wd_context_node,
      lo_el_flighttab type ref to if_wd_context_element,
      lt_flighttab    type  wd_this->elements_flighttab.
* get context node
lo_nd_flighttab = wd_context->get_child_node( name = wd_this->wdctx_flighttab ).
*
lo_nd_flighttab->get_static_attributes_table(
  importing
    table = lt_flighttab
).

* call the method <insert_flights>
call method zcl_net310_flightmodel=>insert_flights
  exporting
    i_flights = lt_flighttab.
endmethod.
7.create_view_wddoinit
method WDDOINIT .
  DATA lo_nd_flighttab TYPE REF TO if_wd_context_node.
  DATA lo_el_flighttab TYPE REF TO if_wd_context_element.
  DATA ls_flighttab TYPE wd_this->element_flighttab.
  data lt_flighttab type zit_flighttab.


* navigate from <CONTEXT> to <FLIGHTTAB> via lead selection
  lo_nd_flighttab = wd_context->get_child_node( name = wd_this->wdctx_flighttab ).
  lo_nd_flighttab->invalidate( ).
  free lt_flighttab.
* @TODO handle not set lead selection
  IF lo_nd_flighttab IS INITIAL.
  ENDIF.

* get element via lead selection
  lo_el_flighttab = lo_nd_flighttab->get_element(  ).

* set attributes
do 5 times.
  ls_flighttab-carrid = ''.
  ls_flighttab-connid = ''.
  ls_flighttab-fldate = ''.
  ls_flighttab-planetype = ''.
  ls_flighttab-seatsmax = ''.
  ls_flighttab-seatsocc = ''.
append ls_flighttab to lt_flighttab.
enddo.
* @TODO handle not set lead selection
  IF lo_el_flighttab IS not INITIAL.
   lo_nd_flighttab->invalidate( ).

  ENDIF.
* alternative access  via index
* lo_el_flighttab = lo_nd_flighttab->get_element( index = 1 ).
* @TODO handle non existant child
* IF lo_el_flighttab IS INITIAL.
* ENDIF.

lo_nd_flighttab->bind_table( lt_flighttab ).

endmethod.
8.delete_data
method DELETE_DATA.
data: lo_nd_flighttab type ref to if_wd_context_node,
*      lt_flighttab type wd_this->elements_flighttab,
      lo_el_flighttab type ref to if_wd_context_element,
      ls_flighttab type wd_this->element_flighttab.

lo_nd_flighttab = wd_context->get_child_node(
  name = if_componentcontroller=>wdctx_flighttab
).
*lo_nd_flighttab->get_static_attributes_table(
*  importing
*    table = lt_flighttab
*).
lo_el_flighttab = lo_nd_flighttab->get_element( ) .
lo_el_flighttab->get_static_attributes(
  importing
    static_attributes = ls_flighttab
).
* calling the method delete in the class zcl_net310_flightmodel
    call method zcl_net310_flightmodel=>delete
      exporting
        sel_carrid = ls_flighttab-carrid
        sel_connid = ls_flighttab-connid.
endmethod.
9.modify_flights
method MODIFY_FLIGHTS .
data: lo_nd_flighttab type ref to if_wd_context_node,
      lt_flighttab    type        wd_this->elements_flighttab.

* get the context node
  lo_nd_flighttab = wd_context->get_child_node(
    name = if_componentcontroller=>wdctx_flighttab
  ).

  lo_nd_flighttab->get_static_attributes_table(
    importing
      table = lt_flighttab
  ).

  call method zcl_net310_flightmodel=>modify_flights
    exporting
      i_flights = lt_flighttab.
endmethod.