SAP CDS Views: Creating a CDS View with an Authorization Check

In this post I am going to demonstrate the creation of a CDS view with an authorization check. Implementing  authorization checks hand in hand with the CDS view is a great way to achieve even more code pushdown.

The example in this post is from the RE-FX module but it can be applied in every module.

I am going to redesign a common report in the real estate, for example the occupation and pull some contract and partner data.

The Data Definition Language (DDL) part looks like this:

In the annotation part it is very important to activate the authorization check.

The authorization check will be executed for the company code (BUKRS).

For this purpose we need to define an access control, the so called Data Control Language (DCL) part.

Usually, we want to integrate the standard SAP authorization checks as they are defined in PFCG.

For the company code we would refer to the dedicated authorization object F_BKPF_BUK.

The DCL grants access to the previously defined DDL zlo_demo. 

The user can see only the company codes for which they are authorized through the authorization object F_BKPF_BUK.

SAP EHS: From Procedural Code to Clean Object Oriented ABAP Part 1

Programming in the SAP EH&S Module can often be callenging due to the concept of properties and characteristis, as well as the different usages (validity areas and ratings).

The BAPIs  BAPI_BUS1077_* from the function group 1077 are still very widely used in procedural code.

Nonetheless, it is the  Object Oriented concept that supports Clean Code. 

Therefore, in order to achieve clean ABAP code for EH&S Developments we can use the class CL_EHCSM_SPC_ACCESS instead of the 1077 BAPIs.

Simple Example:

Here I am going to demonstrate a rework of a procedural function module into a clean code method.

Reading specification properties using the function module BAPI_BUS1077_GETDETAIL:

Procedural code:

SELECT matnr recnroot FROM estmj INTO CORRESPONDING FIELDS OF TABLE lt_estmj WHERE matnr = iv_matnr AND delflg = abap_false.

  lv_lines = lines( lt_estmj ).

  CASE lv_lines.
    WHEN 0.
      ev_return = '1'. 
      RETURN.
    WHEN 1.
      READ TABLE lt_estmj INTO ls_estmj INDEX 1.
    WHEN OTHERS.
      ev_return = '2'. 
      RETURN.
  ENDCASE.



  CLEAR: ls_subheader.

  ls_subheader-record_no = ls_estmj-recnroot.
  APPEND ls_subheader TO lt_subheader.

  ls_propheader-subchacat = 'SAP_EHS_XXX_YYY'.
  APPEND ls_propheader TO lt_propheader.

  ls_propheader-subchacat = 'SAP_EHS_XXX_YYY'.
  APPEND ls_propheader TO lt_propheader.

  ls_propheader-subchacat = 'SAP_EHS_XXX_YYY'.
  APPEND ls_propheader TO lt_propheader.

  ls_propheader-subchacat = 'SAP_EHS_XXX_YYY'.
  APPEND ls_propheader TO lt_propheader.

  ls_propheader-subchacat = 'SAP_EHS_XXX_YYY'.
  APPEND ls_propheader TO lt_propheader.

  CALL FUNCTION 'BAPI_BUS1077_GETDETAIL'
    EXPORTING
      scenario         = '01'
      key_date         = sy-datum
      flg_header       = 'X'
      flg_matjoin      = 'X'
      flg_properties   = 'X'
      flg_prop_data    = 'X'
      flg_prop_details = 'X'
    TABLES
      return           = lt_return
      sub_header       = lt_subheader
      matjoin          = lt_matjoin
      prop_header      = lt_propheader
      prop_val         = lt_propval
      prop_data        = lt_propdata
      prop_usage       = lt_propusage.

In the procedural code we find select statements, which should be avoided.
It is very common in the EH&S Development to be trying to read the specification to a certain material.

Recommendations:

• Avoid direct Selects

First try to find an existing function in your framework and only if nothing is available, write a select statement.

• A BAPI is better than a direct select.  
• The method of a class is better than a BAPI. 

In this example I recommend to capsule the often needed function get_recn_by_matnr in a method. In my method I still had to use the BAPI BAPI_BUS1077_GETLIST  but it is reusable and in case of change, I will change it once.

zcl_ehs_hazard=>get_recn_by_matnr. 

• Use INSERT VALUE instead of APPEND

Appended lines need a defined type. The INSERT VALUE is more flexible and can be used even if some structure type gets changed.

• DRY (DO NOT REPEAT YOURSEF)

In the above code we see that many properties were hard-coded and appended to the properties  header table. In similar cases it is worth considering to move such logic to the configuration (you can use a z-table instead of the hard code). The advantage is that when business asks for an additional property to be evaluated, you can simple do this as a customizing activity, not affecting your code.

You can see in the clean code that the logic is capsuled in the method 

zcl_ehs_hazard=>get_XYZ_vat.

• Use ABAP OO instead of procedural code

In this example ( BAPI_BUS1077_GETDETAIL vs. CL_EHCSM_SPC_ACCESS) we can easily see the advantages of using the dedicated method retrieve_val_char_data of the class 
 CL_EHCSM_SPC_ACCESS. 

The method  retrieve_val_char_data  provides the option to filter the characteristics by usage. This means that if I want to evaluate a certain usage, for e.g. Validity Area Korea, I can filter before I get the data and don't have to worry afterwards. 

• Prefer inline declaration always when it is possible, when not declare the variables close to their usage

With the OO Style we can use inline declarations for the import parameters (clean code)

• Avoid hard code or the so called magic words

You can see the hard coded scenario '01' in the procedural code. Usually, you can find the constants that you need in the interface. In the clean code, for example, we use if_ehcsm_spc_const_c=>gc_lockmode-no_lock.

Not everyone knows what '01' or 'N' is but everyone will understand 'no lock'.

• Call your variable and methods in a way that they can be pronounced

This makes your code more readable and the hand-over process more efficient.

Clean ABAP Code:

    METHOD XYZ.
    DATA(lo_access) = cl_ehcsm_spc_access=>get_instance( ).
    DATA lt_key TYPE ehcsmt_spc_key.
    DATA lt_usage_filter TYPE ehcsmt_spc_usage_filter.
    INSERT VALUE #( recn = zcl_ehs_hazard=>get_recn_by_matnr( iv_matnr ) ) INTO TABLE lt_key .
    INSERT VALUE #( rvlid = iv_country vaclid = zcl_ehs_hazard=>c_vaclid ) INTO TABLE lt_usage_filter.
    lo_access->retrieve_val_char_data(
      EXPORTING
        it_spc_header_key    = lt_key
        it_vat               = zcl_ehs_hazard=>get_XYZ_vat( ) 
        it_spc_usg_filter    = lt_usage_filter
        iv_lock_mode         = if_ehcsm_spc_const_c=>gc_lockmode-no_lock
       IMPORTING
         et_spc_val_char_data = DATA(lt_spc_char_data)
         et_message           = DATA(lt_message)
         ev_severity          = DATA(lv_severity)
    ).

The most important is to use your framework and what it offers because it is tested!
Good luck!