Hi,
when I call code residing in SAP DB, that is DBPROCs, what options
do I have to reduce calling overhead? I'd guess:
1. pack multiple invocations into one wire packet ("BULK CALL")
2. make a single invocation with "structured array data" as In/Out
parameter ("Stream")
Browsing through docs/code, I found some hints what specific SAP DB
features could do above .. but more questions are left and hints
would be welcome:
MASS CMD with DBPROCs
The docs about the application level protocol used between clients
and SAP DB tasks talks about "MASS CMD". Multiple rows may be
transmitted in one package for INSERT/DELETE/UPDATE and also SELECT
for reasons of efficiency ("ODBC SQLBulkOperations"). Is it possible
to use this also to call DBPROCs with mass sets of IN parameters or
is it unavoidable that every DBPROC CALL results in a network round-trip?
ABAP Tables and LC Streams
ABAP Tables and LC Streams as In/Out parameters in C++ LC procedures.
Is this exclusively supported by the C/C++ SQL precompiler or also
available as some proprietory ODBC extension (that is, at API call level)?
My understanding was, that ODBC is supposed to be the "native" call
level API to SAP DB. But if it doesn't support advanced features, then
one has to use the precompiler or go down to the wire protocol level?
Btw. at least for JDBC, Oracle has done something very nice to support
REFCURSOR parameters (similar to ABAP tables / LC streams) from JDBC.
They simply defined another bind variable type (OracleTypes.CURSOR)
which can be handled like another ResultSet after binding:
import oracle.jdbc.driver.*;
...
CallableStatement cstmt;
ResultSet cursor;
// Use a PL/SQL block to open the cursor
cstmt = conn.prepareCall ("begin open ? for select ename from emp; end;");
cstmt.registerOutParameter (1, OracleTypes.CURSOR);
cstmt.execute ();
cursor = ((OracleCallableStatement)cstmt).getCursor (1);
// Use the cursor like a normal ResultSet
while (cursor.next ())
{System.out.println (cursor.getString (1));}
http://technet.oracle.com/tech/java/sqlj_jdbc/htdocs/jdbc_faq.htm#_51_
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