I currently have an application that was written in VFP 5.0 and running on Windows XP machines with the database stored on a Windows 2000 server. It was first installed in 2000 and has had modules added, the most recent being 6 months ago.
However, I have been having some problems with the program seeing that the database sizes has grown considerably with at least 2 tables having over 20000 records.
The hardware technician has indicated that their server needs to be replaced and said I should look into making my application a client/server one. Right now, it is in a flat file format. However I am totally new to this and have no idea how or where to start.
Can anyone point me to some books that will assist me. Also, will I have to completely change the code used to access my tables in reading and writing to them I need to present a proposal for client/server software and changes to the company as soon as possible so I can have new version completed by March.
Thanks
Moving from VFP 5.0 to client/server
Gergely Varadi
I do not know why you are using a 'flat file' (I assume some kind of TXT, CSV, SDF like )
VFP is perfectly capable of using relational databases (DBF) where 20,000 records is nothing. You can have millions of records and as long as one file does not reach the limit of 2GB (per file) you will have no problems.
VFP can also do Client/Server (2-Tier) architexture or even more (N-Tier) but it will probably mean completely changing the architecture of your program. Depending on how it was written, it could be a very simple change to go Client./Server or it could mean a complete re-write.
We do not have enough information from you but it sounds like a re-write.
To use Client-Server with an external database like SQL Server or similar, you should read the chapter on it in Help.
Also read about the following:
Buffering
SQL Pass-Through (SPT) - SQLConnect() - SQLStringConnect() - SQLExec(), etc.
CursorAdapter (not available in very old versions like VFP 5.0)
Remote Views
Also a book like "Client-Server Applications with Visual FoxPro and SQL Server 7" (http://www.hentzenwerke.com/catalog/csvfp.htm) even though written for VFP 7.0 will help.
BTW, VFP 5.0 is a very old version,. You should consider upgrading to VFP 9.0. The difference in power and capabilities is tremendous!
gags007
I know, it's not a good solution, because of heavy network load, unnecessary data moving between the server and the client. It was just a short test, what took only some hours.
The next step is to use SQL Pass Through of course, to optimize the database access, searches and network load.
Aaron Moore
This is the code I have which starts my program:
STORE SPACE(25) TO THEFILE
SET TALK OFF
SET CONFIRM ON
SET SAFETY OFF
SET CENTURY ON
SET ESCAPE OFF
SET EXACT ON
SET ANSI ON
APPLICATION.VISIBLE = .F.
SET DATE MDY
SET HELP TO C:\HELP.HLP
CLOSE DATA ALL
USE C:\DATA_PATH
IF EMPTY(APP_PATH)
MESSAGEBOX("NO DATABASE PATH FOUND"+NEWLINE+;
"THE V.R.S SETUP WAS NOT COMPLETED"+NEWLINE+;
"CONTACT YOUR SYSTEM ADMINISTRATOR",16,"V.R.S Critical System Error")
QUIT
ELSE
STORE ALLTRIM(APP_PATH) TO SYS_PATH
ENDIF
STORE SYS_PATH +"\OPERATOR.DBF" TO THEFILE
IF !FILE(THEFILE)
MESSAGEBOX("INVALID DATABASE PATH"+NEWLINE+;
"THE V.R.S SETUP WAS NOT COMPLETED"+NEWLINE+;
"CONTACT YOUR SYSTEM ADMINISTRATOR",16,"V.R.S Critical System Error")
QUIT
ENDIF
SET PATH TO &SYS_PATH
OPEN DATABASE mydb SHARED
SET DATABASE TO mydb
ON ERROR DO FORM ERRORS WITH ERROR( ), MESSAGE( ), MESSAGE(1), PROGRAM( ), LINENO(1)
DO FORM SPLASH_FORM
READ EVENTS
CLOSE DATA ALL
CLEAR ALL
QUIT
The hardware technician stated that the cache available on the server is not enough to allow my program to run as well as the other documents which the users access from the server. There are currently 8 users which use the system. The files on the server are dbf tables.
Errors I have been having recently involve some such as:
Error loading file - record number 89. Left = 137 Top = 20 Width = 90 Height = 90 Alias = "receipt_q" CursorSource = ..\v_work_area\receipt_q.dbf Name = "Cursor1" <or one of its members>.Methods : Object file c:\officer_rec.fpt
I run the same application on my system and it works.