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Order in fpt file entries
Message
De
25/09/2008 19:24:06
Neil Mc Donald
Cencom Systems P/L
The Sun, Australie
 
 
À
22/09/2008 16:54:30
Calvin Smith
Wayne Reaves Computer Systems
Macon, Georgie, États-Unis
Information générale
Forum:
Visual FoxPro
Catégorie:
Codage, syntaxe et commandes
Versions des environnements
Visual FoxPro:
VFP 9 SP2
OS:
Vista
Network:
Windows 2008 Server
Database:
MS SQL Server
Divers
Thread ID:
01349628
Message ID:
01350840
Vues:
15
Hi,

A busted FTP is difficult to repair, remember there is no backlink from the FTP to the DBF, the only link is the block pointer stored in the DBF memo field.

All memo data for a record should be contiguous in the FPT.

Remember the data can be anywhere in file, because of the fact that if you edit a memo field and the block size is exceeded during the edit, all blocks related to that record will be moved to the end of the file and the original data is just left where it was, that is how you get FPT bloat.

As you can see you can spend a lot of time linking memo data back to the DBF record only to find that it is old data from several edits ago, packing does get rid of the old unlinked blocks and it resets the DBF to point to the new block position.

Most FTP damage I have observed occurs when someone terminates a pack process half way thru, the file is left usuable.

>If I look at an FPT file in a text editor, what order are the entries in? In other words, this FPT file may have multiple entries for each customer. If I just open the FTP file in a text editor, the data appears to be order for an individual account but how would the order in the FTP file relate to the entry order of the associated DBF? My problem is that I have to relate the entries in the FTP file to account numbers that are not referenced in the content of the memo field.
Regards N Mc Donald
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