Main   Products   Offshore Outsourcing   Customers   Partners   ContactUs  
JDBC Databases
  HXTT Access v5.2
  HXTT Cobol v2.1
  HXTT DBF v5.2
 
  Buy Now
  Support
  Download
  Document
  FAQ
  HXTT Excel v4.2
  HXTT Paradox v5.2
  HXTT Text(CSV) v5.2
  HXTT XML v1.2
Offshore Outsourcing
Oracle Data Import/Export
DB2 Data Import/Export
Sybase Data Import/Export
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
   
   
   
Hongxin Technology & Trade Ltd. of Xiangtan City (abbr, HXTT)

HXTT DBF
Will this expressions use indices
John
2006-04-04 23:38:55.0
First example:
select bcode from mbook where STR(BCODE,6)+movtype>' 1Y'

Second example:
select bcode from mbook where STR(BCODE,6)+movtype=STR(BCODE,6)+'Y'

Please, help me?
Re:Will this expressions use indices
HXTT Support
2006-04-04 23:47:15.0

If your index expression is STR(BCODE,6)+movtype, you can use
select bcode from mbook where STR(BCODE,6)+movtype>' 1Y'

STR(BCODE,6)+movtype=STR(BCODE,6)+'Y' won't utilized index.


Re:Re:Will this expressions use indices
john
2006-04-05 00:40:15.0
Thanks!
If I have next index 'STR(BCODE,6)+DTOS(opdate)'. What expression I must write for select records where field opdate<2005-12-01 and bcode is a number.
Re:Re:Will this expressions use indices
john
2006-04-05 00:48:03.0
Thanks!
If I have next index 'STR(BCODE,6)+DTOS(opdate)'. What expression I must write for select records where field opdate<2005-12-01 and bcode is a number.
Re:Re:Re:Will this expressions use indices
HXTT Support
2006-04-05 00:54:44.0

You can use STR(BCODE,6)+DTOS(opdate)>=' 120051201'.

BTW where STR(BCODE,6)=' 1' can utilize STR(BCODE,6)+DTOS(opdate) too.

Re:Re:Re:Re:Re:Will this expressions use indices
John
2006-04-05 01:01:37.0
Thanks a lot!
Will this expressions use indices
John
2006-04-05 01:26:20.0
Why when I use order by or max(exp). It's very slow.
Re:Re:Re:Re:Re:Re:Re:Will this expressions use indices
HXTT Support
2006-04-05 01:40:07.0
HXTT DBF supports to utilize index for ORDER by clause, when there's no where clause.
For max(exp), HXTT DBF need to do aggregate calculation and filter all deleted rows.
What's your sql?
Re:Re:Re:Re:Re:Re:Re:Re:Will this expressions use indices
John
2006-04-05 01:53:52.0
select bcode, max(opcode), min(opdate) from mbook
where STR(BCODE,6)+movtype>' 1Y' and
STR(BCODE,6)+DTOS(opdate)>=' 120051201'
group by bcode
Re:Re:Re:Re:Re:Re:Re:Re:Will this expressions use indices
HXTT Support
2006-04-05 02:11:37.0
You can try:
select bcode, max(opcode), min(opdate) from mbook
where BCODE>=1 and movtype>'Y' and opdate>={d '20051201'} group by bcode

since that where clause need less cacluation.

Will this expressions use indices
john
2006-04-09 23:42:42.0
Why when I try search fcode=12 and opdate between date1 and date2
using index "STR(FCODE,5)+DTOS(OPDATE)" I've recive fcode = 15, 16 .. etc.
But I need only fcode=12
Re:Re:Re:Re:Re:Re:Re:Re:Will this expressions use indices
HXTT Support
2006-04-10 02:00:41.0
What's your sql?

Search Key   Search by Last 50 Questions




Google
 

Address: 9 Station Rd., Xiangtan City, Hunan Province, P.R. China
Postcode: 411100
Phone: (86)731-58225727
Fax: (86)731-58225727
Email: webmaster@hxtt.com
Copyright © 1999-2011 Hongxin Technology & Trade Ltd. | All Rights Reserved. | Privacy | Legal | Sitemap