ABAP_to_the_Future

15
ABAP Programming for SAP HANA
METHOD get_complex_monster_data
IMPORTING VALUE( this_and_that ) TYPE whatever
VALUE( id_client ) TYPE sy-mandt
EXPORTING VALUE( the_other ) TYPE something_else.
Listing 15.11 Class Definition with Interface to Enable Use of AMDPs
Although the CDS views discussed in Sect ion 15.2.1 are more or less database
independent, AMDPs are specific to SAP HANA. This is why _HDB (for “HANA
database”) appears at the end of the inte rface name shown in Listing 15.11. The
other point you may be puzzled about in Listing 15.11 is that you have to tell the
SAP HANA database what client you’re talking about, and thus the method needs
to get the client ( MANDT) as an importing parameter. In the ABAP world, you’re
used to the system automatically reading or writing to the client where the program
is running—but in the database world, the client is a vital piece of information.
(As mentioned in Section 15.2.1, when coding a DDL for a CDS view, you
don’t have to pass in the client; the runtime system handles it.)
Did you also notice that you have to pass everything by value? That’s compulsory
if you want a method to make use of an AMDP.
Implementing the ABAP Method Using an AMDP in SQLScript
If you just did a normal implementation of a method of a class defined as shown
in Listing 15.11 with normal ABAP code , then it would run in the application
server as normal. However, this isn’t wh at you want, so you have to tell the
method implementation to behave differently.
You can control whether a method is run on the normal ABAP application server
or within the database by adding some extra lines to the implementation of the
method. This is shown in Listing 15.12.
Warning: Houston, We Have a Problem
If you put the word SQLSCRIPT in lowercase, Eclipse gets really upset. Conversely the
word hdb has to be in lowercase.
CLASS zcl_monsters IMPLEMENTATION.
METHOD get_complex_monster_data
BY DATABASE PROCEDURE
FOR hdb
LANGUAGE SQLSCRIPT
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