FreeTDS Development Group

["Schörk, Andreas" <andreas.schoerk AT infor.de>]

Hello,
I do not know how it is solved on tds-level, but I can describe a little 
how it is handled when you use ODBC or OLEDB.
When you execute multiple statements in mssql in one go
(normally it´s called batch) including more than one select, you get
multiple resultssets back.

These are the complete results of each query in the batch.
There you do not fetch single records from different statements alternating.
In your programcode you can first fetch the first resultsset when it is done
you can handle the next and so on.

The same is returned, when you call a procedure returning the results 
of more than one selectstatements.
This is the case when the results of these statements  are not eaten up 
by using cursors or variables.

The disturbing fact seems to be that with sqlserver you always have max. one
resultsset per connection opened. To handle more than one the same time
you have to open so called server-side cursors by a special commands or by 
using special stored procedures. But if you do this, work with more than one
cursurs the same time on a connection reading data from the server will slow
down about 5 to 10 times compared with reading it separately.
hope this helps to clarify a bit.

Andreas

-----Ursprüngliche Nachricht-----
Von: Nil Alexandrov [mailto:nil AT internet2.ru]
Gesendet: Mittwoch, 8. November 2000 15:21
An: TDS Development Group
Betreff: [freetds] Multi statement SQL


Hello !

   I don't understand how can I use multi statement in MSSQL - how does it
work. In other SQL databases - the first, I create database connection
handle, than, I can create transaction handle based on database connection
handle, than I can use many statement handle base on transaction handle at
the same time.

   So, I can start 'select ...', than fetch some rows, start another
'select ...' and fetch from the first statement and from the second
statement at the same time.

   How does it implement in TDS level ? I need to create new connection to
SQL Server to start new statement, isn't it ?

Best regards, Nil.
E-Mail: nil AT internet2.ru


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