Main   Products   Offshore Outsourcing   Customers   Partners   ContactUs  
JDBC Databases
  HXTT Access v7.1
  HXTT Cobol v5.0
  HXTT DBF v7.1
 
  Buy Now
  Support
  Download
  Document
  FAQ
  HXTT Excel v6.1
  HXTT Paradox v7.1
  HXTT PDF v2.0
  HXTT Text(CSV) v7.1
  HXTT Word v1.1
  HXTT XML v4.0
Offshore Outsourcing
Free Resources
  Firewall Tunneling
  Search Indexing Robot
  Conditional Compilation
  Password Recovery for MS Access
  Password Recovery for Corel Paradox
  Checksum Tool for MD5
  Character Set Converter
  Pyramid - Poker of ZYH
   
   
   
Heng Xing Tian Tai Lab of Xi'an City (abbr, HXTT)

HXTT DBF
HXTT and deletes from Foxpro tables
Kevin M Penrose
2020-01-29 09:51:17.0
I have noticed HXTT is permanently deleting the records in FoxPro. Is there an option/flag to mark it for deletion?
Within FoxPro deletion is a two-step process. First the record is marked for deletion then you issue a PACK command to permanently remove the record. See image below showing records marked for deletion when browsed in FoxPro
The PACK command requires exclusive access to the table. I am curious as to how this is being done in HXTT when the table is in shared use.
We have been using HXTT for a few years, and never realized that deletion in Foxpro is a two-step process, and I was wondering if the way that HXTT does deletions causes performance issues while doing deletes.
Re:HXTT and deletes from Foxpro tables
HXTT Support
2020-01-29 17:32:27.0
You can use deletesAreVisible=true connection property to see the deleted rows.
deletesAreVisible: Indicates whether DBF's resultSet includes deleted records. false


DELETED([cTableAlias | nWorkArea]): returns a logical value that indicates whether the current record is marked for deletion.



Re:Re:HXTT and deletes from Foxpro tables
Kevin
2020-01-30 06:51:07.0
I'm aware of the deletesAreVisible flag, my question, more precisely, is what does HXTT do when it receives an SQL statement that calls delete for a number of records. Are those records simply marked for deletion, or does HXTT do a mark for delete followed by a pack to actually delete the records from the table. I think it is doing the latter, because the records I'm deleting are in fact removed from the table. I'm asking because I'm trying to isolate a performance issue, and I'm trying to rule out a speed degradation due to the need for an exclusive lock to do the pack operation after a mark for delete.
Thanks!
Re:Re:Re:HXTT and deletes from Foxpro tables
HXTT Support
2020-01-30 16:58:08.0
> Are those records simply marked for deletion,
Yeah. If deletesAreBlank=false(default connection property), you can undelete it. If deletesAreBlank=true, it becomes a blank data row.
deletesAreBlank Indicates whether one destination data record will become one deleted blank record when delete it. false

>does HXTT do a mark for delete followed by a pack to
>actually delete the records from the table.
Pack Table sql can do it, but HXTT DBF markes a deleted flag.

>because the records I'm deleting are in fact removed from the table.
You can see those deleted rows if you use deletesAreVisible=true connetion property in that(or latter) connection.

>the need for an exclusive lock to do the pack operation after a mark for delete.
Yeah. Pack table sql need an exclusive lock.




Search Key   Search by Last 50 Questions




Google
 

Email: webmaster@hxtt.com
Copyright © 2003-2019 Heng Xing Tian Tai Lab of Xi'an City. | All Rights Reserved. | Privacy | Legal | Sitemap