Write an AMDP that respects MANDT

Open SQL injects the client automatically, but AMDP does not: SQLScript runs on the database and sees the raw tables, so a careless table function returns rows from every client. A cross-client leak is a real defect, not a style nit, and the fix is to handle MANDT explicitly at three points that must agree.

First, the client column must appear both in the table function's returns list and in the underlying source SELECT, so the client travels with each row. Second, you declare a parameter annotated @Environment.systemField: #CLIENT typed abap.clnt; the framework binds the caller's client into that parameter at runtime. Third, the SQLScript body filters on it explicitly with a predicate such as where mandt = :p_client.

Because nothing in the language forces this, you confirm it with tooling: ATC's AMDP client-handling check flags a table function or procedure that reads a client-dependent table without filtering the client. Enable that check in your variant so the safety net catches the omission that the compiler will not.

ABAPmethod get by database function for hdb
           language sqlscript
           options read-only
           using zorder_hdr.
  return
    select order_id as "OrderId", kunnr as "CustomerId", total
      from zorder_hdr;
endmethod.

ABAPdefine table function zi_orderranking
  with parameters
    @Environment.systemField: #CLIENT
    p_client : abap.clnt
  returns {
    client     : abap.clnt;
    orderid    : zorder_id;
    customerid : kunnr;
  }
  implemented by method zcl_order_ranking=>get;

method get by database function for hdb
           language sqlscript
           options read-only
           using zorder_hdr.
  return
    select mandt as client, order_id as "orderid", kunnr as "customerid"
      from zorder_hdr
      where mandt = :p_client;
endmethod.

Source notes: clean-core-curriculum §12.8