Technical Information Database
TI247B.txt BDE setup for Peer-To-Peer(Non-Dedicated) Networks
Category :General Programming
Platform :All
Product :BDE 3.0
Description:
Using a BDE32 Application on a Peer-To-Peer Network
---------------------------------------------------
A Peer-To-Peer network (a network where each machine acts
as a client and a server) can be one of the following,
including other network platforms that are compatible
with these:
1) Windows 95
2) Windows NT
3) Lantastic
4) Netware Lite
The BDE automatically detects when tables reside on a
network drive, but it cannot detect whether the tables
are on a dedicated server or a server/client. Dedicated
servers notify client applications that a file has been
modified or locked. This functionality is not present in
Peer-To-Peer (non-dedicated) networks. To achieve this
functionality with Peer-To-Peer networks set "LOCAL
SHARE" to TRUE in the BDE Configuration Utility on the
System page. This must be done on all BDE clients that
access the tables on networks listed above. This is not
necessary for Novell File Server type networks.
If the tables that are being used are Paradox, there must
also be a directory used for network control. This
directory must also reside on the network for all client
applications to use. It is good practice to have a
separate directory for the application, network, and
tables. The following is an example:
(Shared Directory)
|
|--- (Tables Directory)
|--- (EXE Directory)
|--- (Network Directory)
There are two different BDE environments that must also
be considered:
1) Using only BDE 32Bit applications.
2) Using BDE 32Bit applications along with BDE 16Bit
applications.
Setup for 32Bit Only Applications
---------------------------------
The 32Bit BDE fully supports the UNC naming convention
along with long file names. It is recommended that the
UNC convention is used for all BDE network connections.
UNC removes the need for mapped drives. This will allow
access to the tables and network directory without the
user being mapped to the drive. UNC has the following
syntax:
\\(server name)\(share name)\(path)+(file name)
Here is a simple example of a standard BDE alias using
UNC:
Alias: MyUNCAlias
Type: STANDARD
Path: \\FooServer\FooShare\Sharedir\Tables
Default Driver: Paradox
The network directory can be setup in the same fashion:
Drivers: Paradox
Net Dir: \\FooServer\FooShare\Sharedir\NetDir
The network directory can be set at runtime using
session.netfiledir (Delphi) or DbiSetProp (C++ / Delphi)
If for some reason UNC cannot be used with the 32Bit
application, follow directions for using BDE 32Bit and
16Bit applications.
Setup for 16Bit and 32Bit BDE Applications
------------------------------------------
Since the 16Bit Windows API does not support UNC, neither
does the 16Bit BDE. To allow applications to share the
tables, all clients must be mapped to the same directory
on the server. If the server is also used as a client,
all other clients must be mapped to the root of the
drive. Drive letters from client to client do not have
to be identical. Here are some examples of what will and
will not work:
Client1:
Path: X:\ShareDir\Tables
Client2:
Path: X:\ShareDir\Tables
This is OK
Client1: (Also the machine with the tables):
Path: C:\ShareDir\Tables
Client2:
Path: X:\ShareDir\Tables
This is OK
Client1: (Also the machine with the tables):
Path: C:\ShareDir\Tables
Client2:
Path: X:\ShareDir\Tables
Client3:
Path: R:\ShareDir\Tables
This is OK
Client1:
Path: X:\ShareDir\Tables
Client2:
Path: X:\Tables (Where X:\Tables is actually
X:\ShareDir\Tables, but shared on the ShareDir directory)
This will not work. The BDE must be able to make the
same entry into the Network Control file.
In Summary (setup for Peer-To-Peer networks):
---------------------------------------------
16 and / or 32Bit Applications:
1) Turn "LOCAL SHARE" to TRUE in the BDE Configuration
Utility.
2) Do not use the UNC naming convention.
3) Do not use tables with long file names.
4) Make sure that all clients are mapped to the same
directory on the server.
32Bit Only Applications:
1) Turn "LOCAL SHARE" to TRUE in the BDE Configuration
Utility
2) Use the UNC naming convention to achieve a path to the
network directory and table directory.
If the above steps are not followed, users could be
locked out of the tables getting error:
"Directory is controlled by other .NET file."
"File: (Path1) PDOXUSRS.LCK"
"Directory: (Path2)"
OR
"Multiple .NET files in use."
"File: (Path) PDOXUSRS.LCK"
Reference:
7/15/98 3:24:23 PM
Last Modified: 01-SEP-99