Paradox On a Network 3

[LWB]

All my Paradox experience is standalone, single user apps that I have "developed". I've never had to deal with the issues of multiple users and I did not consider them in developing various applications.

At work I have a database that tracks projects, budget, and other financial information. Although my computer is on a network the database (and Paradox) exists only on my machine. It would be useful if others (about 10 people) in my group could access the data (but not necessarily edit any of it). I finally convinced someone to get Paradox 10 (I'm using 9) because of the free Runtime. I want to put the data (I assume the entire contents of the Working Directory) on the server and have Runtime installed on the group members computers. All computers are Windows 2000, and the Server is also Windows 2000 (I think, it used to be NT).

What do I need to do to make this happen? What changes do I need to make in my application (modest amount of ObjectPal) to handle this environment? We have computer guys who manage the network that are very helpful, but know nothing about Paradox.

Lynn

 

[Langley]

I'll let Lance give you the long answer, but the short answer is that Paradox handles most of the troublesome issues for you, like record and table locks and such. Without knowing your application design, it is difficult to know what changes might be necessary.

Basically, as long as the individual workstations share a .NET file on the network, then they can coedit data tables. There are some BDE settings to be checked and possibly changed, and you will need to alter aliases to reflect the new location(s) of your data.

Here's a quick and dirty example: You have an address book with one table on a standalone machine that you want to make networkable.

1. Create a directory on your network where the table can be moved. Make sure all workstations can see it and have full access rights to it. Map a network drive to it and assign the same letter to each workstation (drive letters are important to Paradox).

2. Copy the table (and forms, reports, etc..., if you like) to the directory.

3. Open the BDE administrator on each workstation and set the NetFile location to the directory you created on the network.

4. Open Paradox and change any aliases to reflect the new drive letter/location of the data.

5. Turn off opportunistic locking on the server and write behind caching on the workstations.

6. Launch your application normally and go to work. If you've moved your forms to the network, then adjust your links to point there.

7. Check for performance issues and adjust the BDE settings as needed.

Mac

"There are only 10 kinds of people in this world... those who understand binary and those who don't"

langley_mckelvy@cd4.co.harris.tx.us

 

[SuperG]

Is there a way to disable write behind caching in windows xp pro and Windows 2000?

 

[SuperG]

Never mind I found it.

Control Panel >> System >> Hardware >> Device Manager >>
right click on your drives select properties then Policies tab. Uncheck write behind caching.

 

[LWB]

Mac,

Thanks for the advice. Paradox 10 just arrived, so I will be able to experiment with it. And I've already asked the computer people here to download Runtime 10 for me. If I have any problems I'm sure the folks here can help.

SuperG - thanks for telling me how to disable the write-behind caching. I had no clue, and just hoped our computer people would understand that part (and the opportuntistic locking).

Lynn

 

[Langley]

Make sure you check for patches:

ftp://ftp.corel.com/pub/Paradox/

Mac

"There are only 10 kinds of people in this world... those who understand binary and those who don't"

langley_mckelvy@cd4.co.harris.tx.us

 

[LWB]

Mac,

It's Service Pack 3 for WP Office Pro 2002. Got it.

I asked one of my network admin guys about opportunistic locking and he thought he knew what it was, but he had no idea how to turn it off. Can you enlight me?

Does it affect anything else when you turn it off?

When I follow SuperG's info on disabling write behind caching the check box says "write cache". I assume that is the same thing as "write behind caching"? And it only affects the local drives. Is this where it needs to be turned off, or on the server drives?

Again, workstations & server are all Windows 2000.

Lynn

 

[rocmisc]

LWB or anyone,

what do you mean by, (I'm using 9) because of the free Runtime? Does ver 10 not give you free Runtime? Before I buy ver 10 or 11 I'm trying to learn everything I can so please bear with me if this is dumb question.

thanks,
Robin

 

[LWB]

Robin,

With Paradox 9 you had to buy the Developers Edition(more $) to get Runtime. With Paradox 7 and Paradox 8 you bought Runtime as a separate piece of software (it cost more than Paradox).

With Paradox 10 and Paradox 11 (Corel Office Pro 2002 and Office Pro 11) you get Runtime 10 or Runtime 11 as "part" of the package. I say "part", because you have to download it from Corel's website, but you don't pay any extra and as before you have unlimited distribution rights for applications you develop based on Runtime.

Unfortunately these Runtimes do not have a distribution agent bundled with them - it was InstallShield with Paradox 7 and something else (PDE?) with Paradox 9. There is info on the net about using other distribution agents (ie Inno).

Runtime makes sense if lots of people need to use the database application you developed, but they don't need to be able to change forms or create new queries or things like that.

Lynn

 

[Langley]

As far as I have been able to determine, there is no negative effect of turning off opportunistic locking to other applications. It helps prevent database corruption.

The 'write cache' checkbox is the correct thing to uncheck on the local drive.

Mac

"There are only 10 kinds of people in this world... those who understand binary and those who don't"

langley_mckelvy@cd4.co.harris.tx.us

 

[LWB]

Mac,

Glad to hear there is no impact on other apps. So, can you (or someone) tell me how to turn off opportunistic locking in Windows 2000 Server?
Lynn

 

[Langley]

I usually get the network admin to do it, so I'm no help there.

Mac

"There are only 10 kinds of people in this world... those who understand binary and those who don't"

langley_mckelvy@cd4.co.harris.tx.us

 

[footpad]

LWB,

Check out

http://bdesupport.com/stability.htm

for some fairly detailed instructions showing how to turn off Optimistic Locking. You'll need to do this for the server, as well as each Windows NT, 2000, and XP workstation that accesses the server.

There *is* an impact for other programs, as it does affect performance for programs that access the hard drive heavily, such as database programs. However, this is hardly noticeable with today's hardware. It was more noticeable in the "old" days (when we measured processors in MHz instead of GHz, but the data integrity benefits far outweigh any performance degradation.

Hope this helps...

-- Lance

 

[hcts]

We have developed a full accounting package for Contractors in the Pdox base and have been supporting it on networks for about 11 years. A few things to consider:

1 Turn off opp locks on the server, they do cause slow downs and lock ups in Pdox.

2. Set your .net file in a directory of its' own. I use a ?:\NETDIR for it.

3. If you do much with CHANGETO, INSERT, DELETE querys, You will have to modify your code to ensure that you have a full lock on the table to be modified. I switched to TCursors instead. Was better in a multi-user situation & I could use the info for my own status bars.

4. Novell is more forgiving on reboots, a workstation reboot on Server 2000 gives a better than even chance of corrupting your tables.

5. Put your FSL's and RSL local, the app will work a lot faster that way. I can give you some tips on how to make maintance easier if that is a problem.

6. Map your data path with a network drive for 2000 workstations, not sure why but it goes faster and is more reliable too.

7. Get rid of any tables that don't need to be in your data model. All those tables will still take file handles and locks over the net. Less is More.

Hope that helps

James D. Howard

 

[LWB]

Lance & James,

Thank you for all the useful info. So far, my Network administrators are reluctant to change the server settings. And since the database is really only out there for informational purposes (the users are not supposed to edit anything, and the changes are made on my computer and then copied to the server) perhaps these problems will not occur. If they do, Network Admin will consider making changes. Our network has maybe 70 users (of which about 10 will have access to the Paradox Runtime application), and no outside connections, and most of the usage is just MS Office. The Network guys are not used to users like me asking for network level changes (that they don't really understand).

Lynn