ABAP_to_the_Future

15
ABAP Programming for SAP HANA
@ABAPCatalog.sqlViewName: 'ZV_MONSTERS_PARAMETERS'
Define view zcds_monster_parameters
with parameters p_sanity_low:ZDE_MONSTER_SANITY,
p_sanity_high:ZDE_MONSTER_SANITY,
p_color:ZDE_MONSTER_COLOR
As select from zt_monsters
{ key monster_number,
monster_name,
color,
sanity,
strength }
WHERE color = p_color AND
sanity between p_sanity_low and p_sanity_high;
Listing 15.8 Defining a CDS View with Parameters
From your program, you then write a statement like the one in Listing 15.9.
SELECT *
FROM zcds_monster_parameters(
p_color = @p_color,
p_sanity_low = @s_sanity-low
p_sanity_high = @s_sanity-high )
INTO TABLE @(lt_colorful_mad_monsters).
Listing 15.9 Calling a CDS View with Parameters
You could also have a mixture of parameters and normal WHERE clauses. The main
advantage of parameters is that inside CDS views you can call functions, and an
input parameter to the CDS view as a wh ole can be passed in to function calls
made within the CDS view. With WHERE clauses, you can only refer to the list of
database fields defined in the view; parameters can be anything you feel like.
As of ABAP version 7.4 SP 8, there is on ly support for some databases (e.g., SAP
HANA) to enable an ABAP program to do a SELECT on CDS views with parameters.
The roadmap from SAP says that, ultimately, all databases will be able to take
advantage of this feature.
View Appends
Another gap that has been plugged is that, previously, if SAP had created a view, then
in SE11 you could add an APPEND structure to it with some fields of your own (e.g., Z
fields you have added to VBAK). You could not do this in SAP-supplied CDS views until
ABAP 7.4 SP 8; thereafter, you can get the same result by creating a DDL as follows:
@AbapCatalog.sqlViewAppendName: 'ZA_STANDARD_EXTENSION'
extend view standard_thing with zcds_standard_extension
668