Re: [GENERAL] Can PostGreSQL handle 100 user database - more info

2000-11-30 Thread Adam Lang 

But there is an OLE DB provider for ODBC, so you can use ADO with an ODBC;
just not as nice.

As for the multiple connections thing, I do not know anything about that.

Adam Lang
Systems Engineer
Rutgers Casualty Insurance Company
http://www.rutgersinsurance.com
- Original Message -
From: "Elmar Haneke" <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Thursday, November 30, 2000 1:59 PM
Subject: Re: [GENERAL] Can PostGreSQL handle 100 user database - more info


>
>
> [EMAIL PROTECTED] wrote:
> >
> > I am not sure what an ole db provider is? This must be another method of
> > talking to the server from a client application. What advantages does it
have?
>
>
> If you intend to use ADO you need an OLE-DB provider.
>
> > I have the open source ODBC client (and I know a Java version exists),
it seems
> > ok but I don't know if it handles things like transactions and other
advanced
> > functions.
>
>
> The ODBC midht cause some "interesting" trouble since VisualBasic
> tends to open multiple connections to the Server. This has tow
> disadvantages:
>
> 1. While using transaction isolation (not reading uncommitted data)
> you cannot read the data written on one connection over another one.
> If this does happen you might not immediately notive the rubbish
> happening.
>
> 2. With 100 users it might significant if there are 500 simultaneous
> connections open. At leas you have to raise the connection-limit.
>
> Elmar

Re: [GENERAL] Can PostGreSQL handle 100 user database - more info

2000-11-30 Thread Elmar Haneke 



[EMAIL PROTECTED] wrote:
> 
> I am not sure what an ole db provider is? This must be another method of
> talking to the server from a client application. What advantages does it have?


If you intend to use ADO you need an OLE-DB provider.

> I have the open source ODBC client (and I know a Java version exists), it seems
> ok but I don't know if it handles things like transactions and other advanced
> functions.


The ODBC midht cause some "interesting" trouble since VisualBasic
tends to open multiple connections to the Server. This has tow
disadvantages:

1. While using transaction isolation (not reading uncommitted data)
you cannot read the data written on one connection over another one.
If this does happen you might not immediately notive the rubbish
happening.

2. With 100 users it might significant if there are 500 simultaneous
connections open. At leas you have to raise the connection-limit.
 
Elmar

Re: [GENERAL] Can PostGreSQL handle 100 user database - more info

2000-11-30 Thread Adam Lang 

Replies inline.

Adam Lang
Systems Engineer
Rutgers Casualty Insurance Company
http://www.rutgersinsurance.com
- Original Message -
From: <[EMAIL PROTECTED]>
To: "Adam Lang" <[EMAIL PROTECTED]>
Sent: Thursday, November 30, 2000 12:40 PM
Subject: Re: [GENERAL] Can PostGreSQL handle 100 user database - more info


>
>
> I am not sure what an ole db provider is? This must be another method of
> talking to the server from a client application. What advantages does it
have?

Yes.  It is an abstraction layer, but it is Windows only technology.  The
way it works is that The database has an ole db provider (much like ODBC).
ADO connects to the database using the ole db provider.  You write your
application using the ADO object model to interact with the database.
Biggest advantage:  as long as you have an ole db provider for that
datasource, your ADO code is universal.

Example.  You have an application that connects to MS SQL Server using ADO
and you extract data, run queries, etc.  Later you migrate to Oracle.  You
change your connection string (which is one line) and in most cases, you can
run your app without any other changes.  ADO is also able to connect to non
relational data sources:  Text files, VSAM, AS/400, etc.  Plus, the ole db
provider should be made to expose the database schema... so you can
manipulate data in an object oriented way, as well as poll the data source
for structure information.  A lot more information is at microsoft's
website.

Also, in a scenario where the data source does not have an ole db provider,
there is one supplied that will connect through ODBC.

>
> I have the open source ODBC client (and I know a Java version exists), it
seems
> ok but I don't know if it handles things like transactions and other
advanced
> functions.

If the ole db provider is made correctly, it should support anything that
the database allows.  I'm not too familiar with using the postgres ODBC
driver.  For the most part, I've come to the point where I have not really
made too many VB apps with a postgres bckend, due to the fact I have to use
the ODBC driver, which is a bit outdated (but it does work).

>
> It would obviously be important to have a good method of talking to P-sql
from
> Windows since a lot of people will want to do this.

That has been my argument that a good connection method is needed to get
into the Windows arena.  Windows developers are spoiled.  No matter how much
you want to bad mouth MS, they do give us some great development tools.
Unfortunately, postgres doesn't have anything to woo any windows develoeprs
over.