ABAP CDS View Parameters: Dynamic Filtering at Runtime

In SAP ABAP CDS Views, you can use parameters to allow dynamic filtering of data based on user input at runtime. These parameters can be defined directly in the CDS view and can be used to filter the data queried by the CDS view.

How to Use Parameters in CDS Views:

Parameters in CDS views are defined using the with parameters clause. This allows you to pass values into the CDS view when it is called or executed, and these values can be used to filter the data.

Basic Syntax for Defining Parameters in CDS Views:

@AbapCatalog.sqlViewName: 'ZFLIGHT_CDS'
@EndUserText.label: 'Flight Data Filtered by Carrier'
define view ZFLIGHT_CDS with parameters p_carrid: s_carrid as select from sflight {
    key carrid,
    key connid,
    fldate,
    price
}
where carrid = :p_carrid

Explanation:

• with parameters p_carrid: s_carrid: This defines a parameter p_carrid of type s_carrid (which matches the type of the carrid field in the sflight table).
• where carrid = :p_carrid: The parameter p_carrid is used to filter the results of the view based on the carrid field. The colon (:) in front of p_carrid is used to reference the parameter.

When the CDS view is executed, the user must provide a value for the parameter p_carrid.

Example: Filtering by Multiple Parameters

You can also use multiple parameters in your CDS view to create more complex filtering logic.

@AbapCatalog.sqlViewName: 'ZFLIGHT_FILTERED'
@EndUserText.label: 'Filtered Flight Data Based on Multiple Parameters'
define view ZFLIGHT_FILTERED with parameters p_carrid: s_carrid, p_minprice: abap.decimal(13,2), p_maxprice: abap.decimal(13,2) as select from sflight {
    key carrid,
    key connid,
    fldate,
    price
}
where carrid = :p_carrid
  and price between :p_minprice and :p_maxprice

Explanation:

• This CDS view has three parameters:
• p_carrid: A parameter for filtering by carrier ID (carrid).
• p_minprice: A parameter for the minimum price.
• p_maxprice: A parameter for the maximum price.
• The WHERE clause filters the data based on the carrid and the price range (p_minprice to p_maxprice).

Using Parameters with Aggregate Functions

You can also use parameters in conjunction with aggregate functions such as SUM, COUNT, etc., in the CDS view.

@AbapCatalog.sqlViewName: 'ZFLIGHT_AGGREGATED'
@EndUserText.label: 'Total Price per Carrier Filtered by Date'
define view ZFLIGHT_AGGREGATED with parameters p_carrid: s_carrid, p_startdate: abap.dats, p_enddate: abap.dats as select from sflight {
    key carrid,
    sum(price) as total_price
}
where carrid = :p_carrid
  and fldate between :p_startdate and :p_enddate
group by carrid

Explanation:

• This view calculates the total price per carrier within a specific date range. The parameters p_carrid, p_startdate, and p_enddate are used to filter the results dynamically.
• sum(price) as total_price: This aggregates the total price for each carrier.
• The WHERE clause uses the parameters to filter by carrid and the date range (fldate between p_startdate and p_enddate).

Using Parameters in ABAP to Call CDS Views

Once you define a CDS view with parameters, you can use it in your ABAP code and pass values for those parameters when calling the view.

Example: Calling a CDS View with Parameters in ABAP

DATA: lt_flights TYPE TABLE OF zflight_cds,
      lv_carrid TYPE s_carrid,
      lv_minprice TYPE abap.decimal(13,2),
      lv_maxprice TYPE abap.decimal(13,2).

lv_carrid = 'LH'.
lv_minprice = 100.
lv_maxprice = 500.

SELECT * FROM zflight_filtered
  INTO TABLE lt_flights
  WHERE carrid = @lv_carrid
  AND price BETWEEN @lv_minprice AND @lv_maxprice.

Explanation:

• In this ABAP code:
• We first define the internal table lt_flights to store the result of the CDS view.
• We define local variables lv_carrid, lv_minprice, and lv_maxprice to hold the values for the parameters.
• Then, we use SELECT to query the zflight_filtered CDS view, passing the values of lv_carrid, lv_minprice, and lv_maxprice as filters.

In this way, the CDS view is filtered dynamically based on the values provided by the ABAP program at runtime.

Key Points to Remember:

1. CDS Parameters: Use the WITH PARAMETERS clause to define parameters for dynamic filtering in a CDS view.
2. Filtering: You can use these parameters in the WHERE clause to filter data based on user input.
3. ABAP Layer Integration: When consuming CDS views in ABAP, parameters can be passed and used for filtering the results directly in the ABAP code.
4. Multiple Parameters: You can use multiple parameters together to create complex filters (e.g., range filters, multiple conditions).

By using parameters effectively, you can create flexible and reusable CDS views that adapt to different data filtering scenarios.