Henry
Yes, there are!
ODBC is slow - designed for compatibility not performance. OleDB is, in
theory at least, at little quicker since it is a leaner protocol: ODBC was
designed to present a common and highly rigid/specified view of a database,
and as a result it is generally considered a little 'top-heavy' whereas
OleDB/ADO is leaner, more focussed on getting results. ODBC tends to be a)
used cross platform since ADO is windows specific and b) better for standard
wizard-driven client tools since the model is more predicatble. OleDB is
more geared towards programmers, since the model is a lot looser (there's no
actual requirement to use SQL, for example). Ironically one of the additions
to OleDB was support for chaptered rowsets - that's repeating or multivalued
fields by the way - but Ardent/IBM never added that.
The keys to using ODBC - if you must - are
A) avoid it if you can.
B) Look to use BCI calls out of UniVerse if possible.
It's often much quicker/convenient to push data out to third party systems
from BCI than to pull it through ODBC or OleDB.
C) If A and B don't suit, build a separate reporting account with clean
local dictionaries and pointers to the live data files. Use only D types and
ensure you correctly define all your associations. Set up the @SELECT
clauses and add SQL data types to your dictionaries (field 8). Test
everything using SQL SELECT statements at TCL. Only publish what you
absolutely must - ODBC connections typically begin by iterating through your
schema, and even with the file information cache this can take some time on
connection. Then set up your reporting account using the HS.ADMIN menu, and
unless you're dumb enough to want the world updating your files and filling
up your lock table, set the DEFAULT entry in HS_FILE_ACCESS to READ (on
setup this is set to READ_WRITE which is a really bad idea). If your tools
permit, use passthrough queries using the NATIVE statement as in {NATIVE
'SELECT * FROM MYFILE'} - that can be much quicker. Most tools won't permit
that though.
D) Read up on UO.Net and decide that it would make for a much better
solution...
Brian
> -----Original Message-----
> From: [email protected]
> [mailto:[email protected]] On Behalf Of Martel, Henry
> Sent: 05 March 2009 13:29
> To: [email protected]
> Subject: [U2] ODBC Connection to Universe on HP-UX
>
> We are thinking of changing our application connect to
> Universe through ODBC connections. Has anyone had experience
> doing this?
>
>
>
> Are there any performance issues or considerations that we
> need to be aware of?
>
>
>
> Thanks,
>
> Henry.
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