[Monetdb-developers] need help for extracting BAT

Stefan Manegold Stefan.Manegold at cwi.nl
Thu Jul 29 16:49:16 CEST 2010


Dear Gaetano,

before answering you technical questions in detail --- I'd need (quite) some
time the sort out the details --- I'd suggest to check carefully, whether
(1) you indeed *need* to use MAL, and whether (2) you indeed *need* to get
all data from the DBMS into tyou application to manipulate it there, and
then write it all back to the DBMS ...

About (1):
If you have relational data and initially load is using SQL (e.g., COPY
INTO), why not stick to SQL and standard interfaces/protocols like JDBC or
ODBC to connect your application to the database?

About (2):
What is the added benefit of using a DBMS, in case it is merely used as file
storage --- wouldn't a file system server the same functionality?

About (1) & (2):
The idea and benefits of using a DBMS (over a plain file system) are (among
others) that a DBMS offers standard datamodels (e.g., relations), languages
(e.g., SQL), and interfaces (e.g., ODBC, JDBC), and provides functionalities
(e.g., query optimization, transactions, etc.) that go beyond file systems,
thus that an application does not have to re-implement those.
For instance, SQL is not only a very powerful query language, but also
offers update ("data manipulation") functionally, and my recommendation
would be to try to exploit this functionality as far as possible before (or
even instead of) re-implementing most of it in your application ...

As said, just some general ideas to think about ...

Stefan

On Thu, Jul 29, 2010 at 04:28:12PM +0200, Gaetano Fabiano wrote:
> Hi all, i'm a new user of MonetDB. I worked on MonetDB/SQL and I can use
> well it. Now I need to use MonetDB directly with MAL. But i'm not so able to
> do that.  I run the client with this command on linux:
> 
> mclient -lmal -d database
> 
> So I can write MAL istruction. But I don't need to create a procedure in MAL
> that doesn't access to my data.
> What I need to do is that:
> I need to give the BAT data of my DataBase and put all data on my
> application: example C++ ora Java array, after that I need to manipulate
> this BAT with my application and update the original BAT.
> 
> How can I do that?
> summarizing i need:
> 
>    - Access to the BAT of the table of my Database.
>    - Print it on monitor
>    - Put it in array, file, stack, or any DataStruct with any programming
>    language.
>    - Set my manipulated BAT again in MonetDB.
> 
> All of this is possible?
> Someone can help me?
> 
> I'm sorry if I don't know the netiquette of your mailing list but I need to
> do that and I don't know where I could be helped.
> 
> Thanks.
> Gaetano.

> ------------------------------------------------------------------------------
> The Palm PDK Hot Apps Program offers developers who use the
> Plug-In Development Kit to bring their C/C++ apps to Palm for a share
> of $1 Million in cash or HP Products. Visit us here for more details:
> http://p.sf.net/sfu/dev2dev-palm

> _______________________________________________
> Monetdb-developers mailing list
> Monetdb-developers at lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/monetdb-developers


-- 
| Dr. Stefan Manegold | mailto:Stefan.Manegold at cwi.nl |
| CWI,  P.O.Box 94079 | http://www.cwi.nl/~manegold/  |
| 1090 GB Amsterdam   | Tel.: +31 (20) 592-4212       |
| The Netherlands     | Fax : +31 (20) 592-4199       |




More information about the developers-list mailing list