ABAP_to_the_Future

Top-Down Development 15.2
SELECT *
FROM zcds_monsters
INTO lt_specalized_monsters.
Listing 15.6 Calling a CDS View from within an ABAP Program
Latest CDS View Built-in Functions
Just to give an indication of how fast the functionality of CDS views are evolving, at the
time of writing two support packs were released in fairly quick succession: SP 8 and SP
9. In SP 8, a whole bunch of new built-in functions became available—for example,
FLOOR, REPLACE, MOD, ABS, ROUND, and COALESCE. Also in SP 8, support was added for
when the data in the database table is comprised of amounts in different currencies or
quantities in different units of measures. There are built-in functions CURRENCY_CON-
VERSION and UNIT_CONVERSION, which enable the database to convert all the currency
values into Vietnamese Dongs before sending the data back to the application server or
to convert everything into kilograms so that you get a meaningful total quantity.
In SP 9, improvements were made to the lifecycle management of CDS views: Before, it
was very difficult to change an existing CDS view when the existing database table had
data inside it, and now that problem has gone away. In addition, in SP 9 the concept of
an enumeration was introduced into the DDL syntax. Most other programming languages
have this concept; it can best be thought of as a domain with several possible
values for a data element, only defined inside a block of code as opposed to inside SE11.
It’s also possible to code a CDS view with parameters. Again, the process is
slightly different than in traditional ABAP. Transaction SE11 views allow you to
define selection parameters, but they are hard-coded (e.g., the monster color is
set as GREEN). When dynamic selections are required (e.g., the user chooses what
he wants on a selection screen), you would add WHERE clauses in your ABAP program
to restrict what the view brought back. An example of this is shown in Listing
15.7.
SELECT *
FROM zv_monster_views
WHERE color EQ p_color
AND sanity IN s_sanity.
Listing 15.7 Coding Parameters in Traditional ABAP
You can do the exact same thing when re ferring to a CDS view within your program,
but in addition, starting with SP 8, in CDS views you can define them with
parameters that are passed in via the ABAP program at runtime, as shown in Listing
15.8.
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