SAP CDS view自學教程之九：cube view和query view的實作原理

In previous eight steps all we focus on is transactional stuff. This time let’s touch some analytics stuff.

Let’s first create a most simple database table in ABAP backend:

Then create a simple cube view:

@EndUserText.label: 'Jerry cube view'

@Analytics.dataCategory: #CUBE

@VDM.viewType: #COMPOSITE

@AccessControl.authorizationCheck:#CHECK

@AbapCatalog.sqlViewName: 'zprdcube'

define view Z_C_Prod_Cube as select from zprd_query{

  key zprd_query.prod_id,

 zprd_query.prod_text,

 @DefaultAggregation: #MAX

 zprd_query.quantity

}

This cube view has only three fields: prod_id, prod_text and quantity.

For more detail for annotation @Analytics.dataCategory: #CUBE, please refer to SAP help.

Then create a query view on top of the cube view:

@EndUserText.label: 'Jerry query verification'

@VDM.viewType: #CONSUMPTION

@Analytics.query: true

@AccessControl.authorizationCheck:#NOT_ALLOWED

@AbapCatalog.sqlViewName: 'zprdquery'

@OData.publish: true

define view Z_C_Product as select from Z_C_Prod_Cube {

 key Z_C_Prod_Cube.prod_id,

 Z_C_Prod_Cube.prod_text,

 Z_C_Prod_Cube.quantity

Since I use @OData.publish: true, a new OData service is automatically generated when this query view is activated.

We have already discussed how this generation is achieved in this blog:My CDS view self study tutorial – Part 4 how does annotation @OData.publish work.

Once activation is finished, we can do some testing. In ABAP backend I have two entries in the table:

So once we perform the read operation via generated OData service: /sap/opu/odata/sap/Z_C_Product_cds/Z_C_PRODUCT

we can see these two entries are returned in OData response automatically:

Let’s do some further research to find out how these two entries are retrieved from backend.

We have CDS view name as Z_C_Product and the generated OData service based on it has name Z_C_Product_CDS.

Like normal CDS view activation with annotation @OData.publish: true, there is also a new ABAP class @OData.publish: true automatically generated, which has only one method redefined: GET_QUERY_NAME. In this method, a constant attribute is returned.

The content of this attribute: ‘2Czprdquery’.

The biggest difference compared with a normal CDS view activation is: when a query view is activated, the generated OData service data provider class has CL_NAT_ODATA_MODEL_ABS as its super class, giving you a hint that all data retrieved based on this query view will be handled by analytics framework.

While for a normal CDS view, the DPC class has super class CL_SADL_GTK_EXPOSURE_MPC, which means the data access in this case is done by SADL framework.

In order to figure out the detail data access logic implementation by analytics framework, I write the following report to simulate the OData call:

REPORT zcds_get_query_view_data.

DATA(lo_tool) = NEW cl_nat_generic_dpc( ).

DATA(lo_context) = NEW /iwbep/cl_mgw_context( ).

DATA: l_r_rs_gw_columns TYPE REF TO cl_abap_tabledescr,

     l_t_rs_gw_columns TYPE REF TO data,

     lo_request        TYPE REF TO /iwbep/cl_mgw_request,

     lo_detail         TYPE REF TO /iwbep/if_mgw_core_srv_runtime=>ty_s_mgw_request_context,

     ls_detail         TYPE  /iwbep/if_mgw_core_srv_runtime=>ty_s_mgw_request_context,

     lt_header         TYPE tihttpnvp,

     lt_filter         TYPE /iwbep/t_mgw_select_option,

     lt_order          TYPE /iwbep/t_mgw_sorting_order,

     ls_page           TYPE /iwbep/s_mgw_paging,

     ls_header         TYPE LINE OF tihttpnvp.

FIELD-SYMBOLS:

          TYPE        table.

lo_context->/iwbep/if_mgw_context~set_parameter( iv_name  = /iwbep/if_mgw_context=>gc_param_isn

    iv_value = 'Z_C_PRODUCT_CDS' ).

lo_context->/iwbep/if_mgw_context~set_parameter(  iv_name  = /iwbep/if_mgw_context=>gc_param_isv

       iv_value = '0001' ).

lo_tool->/iwbep/if_mgw_core_srv_runtime~set_context( lo_context ).

CREATE DATA lo_detail.

lo_request = NEW /iwbep/cl_mgw_request( ir_request_details = lo_detail it_headers = lt_header ).

DATA(lo_rt) = NEW cl_eq_bics_gw_rt( i_query          = '2Czprdquery'

                                   i_servicetype_oq = abap_true ).

lo_rt->get_designtime(

 IMPORTING

   e_t_column_description = DATA(l_t_query_struc) ) .

l_r_rs_gw_columns = cl_eq_bics_gw_dt=>build_rs_structure( l_t_query_struc ).

CREATE DATA l_t_rs_gw_columns TYPE HANDLE l_r_rs_gw_columns.

ASSIGN l_t_rs_gw_columns->* TO .

ls_detail-technical_request-service_name = 'Z_C_PRODUCT_CDS'.

ls_detail-technical_request-service_version = '0001'.

ls_detail-technical_request-source_entity_type =  ls_detail-technical_request-target_entity_type

= 'Z_C_PRODUCTType'.

ls_detail-technical_request-source_entity_set = ls_detail-technical_request-target_entity_set

= 'Z_C_PRODUCTTypeCollection'.

ls_header-name = 'dummy'.

APPEND ls_header TO ls_detail-technical_request-request_header.

CALL METHOD lo_tool->/iwbep/if_mgw_core_srv_runtime~read_entityset(

 EXPORTING

   iv_entity_name           = 'Z_C_PRODUCTType'

   iv_source_name           = 'Z_C_PRODUCTType'

   is_paging                = ls_page

   it_order                 = lt_order

   it_filter_select_options = lt_filter

   is_request_details       = ls_detail

 CHANGING

   cr_entityset             = l_t_rs_gw_columns

   ct_headers               = lt_header

                              ).

WRITE: 'lines of data: ', lines( ).

With SAT trace I can easily locate the exact location of code where the data retrieve is done:

In this line the DB cursor is opened with generated SQL statement:

Mystery Revealed!

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