Client Server options

[TimStone]

For many years I have been using ADS with my application, and I really didn't intend to change. I have been a reseller, and each year I have sold several licenses. Last year I apparently did not sell enough, and I'm not willing to pay an "annual fee", so I'm likely needing an alternative.

Currently my application is written with xHarbour ( .com ), using the ADS drivers, and FWH. I do want to stay with DBF's. At this point, converting all of my clients to another data format, and rewritting the application, is just not reasonable.

My clients usually have 2 to 5 workstations, but some may have 10 to 20.

1) Using DBFCDX is fine for small peer to peer operations, but how stable is it for larger systems ( and what is the reasonable limit ?)
2) Are there reliable alternatives for DBF Client Server ?

Please don't suggest Terminal Services. That is not an alternative at this time.

Other input would be appreciated. Thanks.

Tim

[Rick Lipkin]

Tim

I have used ADS for many years while I was in State government, however I was persuaded to re-write my applications to run on Sql Server and I have never looked back.

http://fivetechsoft.com/wiki/doku.php?i ... 1216796127

I know that is not the answer you are looking for, but Microsoft has for the past few years offered ( free ) Sql Server Express which would be ideal for 10-20 people running on a dedicated server.

http://www.microsoft.com/sqlserver/en/u ... press.aspx

Above is the link to the MS Sql Express website and the Express database is absolutely free to use... but you will need to re-write all your database calls using ADO ( sqloledb ). Another nice 'gift' MS has provided is there is no need to install a SQL client as it comes standard on all versions of Windows at least through Windows 8.

I will mention, that Microsoft has stated it may phase out or 'diminish' the ADO client after Windows 8, using instead ODBC which I think is a step backward , in favor of its dot net framework.

For now, if it were me, I would stay with ADS ... ADO is very similar to the tData class you are already using so the concept of using classes and methods for data manipulation should already be very familiar to you if you want to make the switch.

Rick Lipkin

[Otto]

> Please don't suggest Terminal Services. That is not an alternative at this time.

Hello Tim,

although you want here it I think it is the way to go. Why don’t you consider using TS.

Best regards,
Otto

[Rick Lipkin]

Otto

If I recall from my MS System Administrator days .. you need to buy Microsoft TS licenses to run on your server for the number of clients you intend to connect ??

Rick Lipkin

[Gale FORd]

Yes, you do need licenses for TS and it does not solve the Client/Server vs direct data issues.
I have 40+ users using direct/non client server data. It works pretty well except sometimes you have to reindex. When you have 40+ users, each one responsible for updating the index, you will eventually have a problem with a computer or network connection failure that breaks the index.

You might look at Apollo and it does have an RDD in xHarbour Commercial. Apollo was written by the original Six driver author. I have not used it so I can't comment on it.
http://www.apollodb.com/apollo_server.asp

[Otto]

Hello Gale,
how does a " computer or network connection failure " effect a program running in a RemoteDesktop session.
You reconnect and you are exactly at the same state as before the failure.


Best regards,
Otto

[TimStone]

OK ... Here are my thoughts on all of these viewpoints:

1) ADS may not be a future option if I can't sell the software. Such a move signals to me that some people "in charge" are making changes in their plans, which might include dumping the ADS division ( its now owned by a much larger company with other interests ).

2) Rich, I do understand the idea of a move to SQL. I actually considered it for my next version since I already have it in play for anything developed with Microsoft tools. I did some research last week to see if I could find a program to convert .dbf to current SQL files, and I hit a dead end. In years past, that was available, but it doesn't appear there is anything current. Also, if I move to SQL, I have to manually go to every user and perform the importing of data from their old system to the new one. Also, I have avoided SQL because in the past, there was huge bloat, and I found the size of the database was about 6 times that of a DBF. I'm not opposed to using SQL ( and it actually could resolve some other issues ), but the data conversion is my main issue.

3) Otto, my clients use a lot of programs, and they simply don't take the time to understand their systems. Connectivity issues cause them stress, but it happens, then I have to clean it up. I'm thinking I don't want to open up the whole new avenue of Terminal Services.

4) I did consider Apollo in the early days, but they were mired in indecision about what they were going to do. I don't hear much about them any longer.

Tim

[Gale FORd]

Otto,
I think we are talking about 2 different things here. Client Server vs Direct is one issue with TS vs Lan another.
Using Direct dbf access, each user is responsible for updating the index regardless if they are on TS or local lan.
In TS if a session is terminated (I do not mean disconnected), a session locks up, a TS server computer failure, network failure (on TS Server), you have the possibility of an index issue.

[norberto]

Tim , are you see Tdolphin from daniel?

[fraxzi]

Dear Tim,

Just my 2cents..

If you have the budget, Stay with ADS.. the server/local are both stable and very easy to administer and in such a tiny footprint works great with [x]Harbour too.

If you want it free, like most of us, prepare for the future by converting .dbf to mysql or similar.. change coding to SQL..
At least on my side, I already started some transitions.. it is inevitable.

There is no gentle dentist..

[sygecom]

take a look LetoDb:
http://sourceforge.net/projects/letodb/
http://www.pctoledo.com.br/forum/viewto ... =42&t=8167
http://itamarlins.blogspot.com.br/2010/ ... viael.html

[MarcoBoschi]

Gale,
>It works pretty well except sometimes you have to reindex.
I reindex directly from server (connected in TS)
It's 10 times faster than from a client

>When you have 40+ users, each one responsible for updating the index, you will eventually have a >problem with a computer or network connection failure that breaks the index.

these problems happen very rarely, if network devices are certified
happened with the old clipper + blinker over coaxial cables and Netware

It would be nice an engine light and free

But Just a question to Tim: is it true that ADS only write and read is directly from client?

[Otto]

Norberto,

thank you for your post.

I will check your concerns about TS.

First I would like to tell you that some years ago I converted all my programs to VB.net, SQL and some to keep it compatible with dbf to
Apollo. To use Apollo from VB is very similar to CLIPPER code. But the database is not as complete as the build in CDX and as far as I know no longer in development. The new product is VISTA DB.

But I am happy to be back with all my programs to FIVEWIN, (x)Harbour and DBF.

Second my programs are for small companies.
The profession “SQL Administrator” is for me warning enough. I never ever heard of a DBF-Administrator as a profession.
If you need a professional to set up a SQL server it is complicated for my purpose and it was (SQL 2000, SQL 2003, SQL ...).

I think we are talking about 2 different things here. Client Server vs Direct is one issue with TS vs Lan another.
Using Direct dbf access, each user is responsible for updating the index regardless if they are on TS or local lan.

If you assume that the coding is done well this should not be a problem in any case.

I will simulate this situations later and let you know what happen.
-In TS if a session is terminated (I do not mean disconnected), a session locks up,
-a TS server computer failure,
-network failure (on TS Server), you have the possibility of an index issue.

--------------------------------------

And if you need remote access over Internet I made the expiriences that client/server is not as stable as TS and not as fast.
To send the changes of the screens is faster than the data.
Next
Remote Access Protocol and technique are developing very fast fastest of all.

You are device (Apple, Linux, Android, … ) independent.


Best regards,
Otto

[Otto]

Hello Tim,

3) Otto, my clients use a lot of programs, and they simply don't take the time to understand their systems. Connectivity issues cause them stress, but it happens, then I have to clean it up. I'm thinking I don't want to open up the whole new avenue of Terminal Services.

Have you seen and tried our RDP-Manager we posted on this forum.

>Connectivity issues cause them stress, but it happens
If this happens the result is the same if you have a CLIENT/SERVER solution or if you work remote.

If you have RDP you can take another device and run the application from there.



Best regards,
Otto

BTW, have you ever tried my AutoCode editor?

[Gale FORd]

Otto,
Thanks for the interest. I still think TS/Citrix is a good way to provide remote operations. We use it in my company also.
You can still have TS/Citrix and Client Server at the same time. That is my point, it is 2 different things.

When you get a lot of people browsing and updating the data at the same time in direct access mode, there is a tremendous amount of file locks on the index file (.cdx). Every time you perform a skip with an active index it has to lock the entire index file before it completes the skip. The more users you have the longer it takes to resolve the contentions. This increases the time window when a problem with a computer or TS session could affect the update of the index.
When it is completely client server it does not have to do this.