Hi,
I have strings like
"2007/14/0001"
"2004/14/0877"
"2008/15/0056"
...
in a very large database.
I need to find all fields containing "/14/" not using the locate command, because it is too slow.
Does anyone have a fast solution for a wildcard search, something like seek "/14/" ?
Thank for any suggestions!
Dietmar
cFiltro := "*" + ALLTRIM(cFiltro) + "*"
(cProducto)->(DBSETFILTER({|| WildMatch(cFiltro, (cProducto)->PRO_DES,(.T.)) },; "WildMatch(cFiltro, (cProducto)->PRO_DES,(.T.))" ))
STATIC aKunden := {}
function SearchFile( suchbeg )
local nLocation, cData
local nOffset := 0
local cDBF := ( "kunden.dbf" )
local nPos := 0
suchbeg := ALLTRIM(Upper(suchbeg))
cData := Upper(MemoRead( cDBF ))
if Len(cData ) < 1
MsgInfo("Not Data to Search","File Error")
Return Nil
endif
nOffset := 0
do while .t.
nPos := INT( AT( suchbeg, cData, nOffset ))
nLocation := INT( ( nPos - Header() ) / RecSize() ) + 1
nOffset := Header() + nLocation * RecSize() + RecSize()
if nPos > 0 .and. nPos < Header()
else
if nLocation < 1
Exit
else
select kunden
goto nLocation
if DELETED() = .F.
aAdd( aKunden, getrec() )
endif
endif
endif
enddo
Return Nil
//------------------------------------------------------------------Hello
You cann use temporary index , it is very faster .
index on field->N1 TAG I_TEMP FOR &(ff) TO TEMP TEMPORARY
TEMPORARY
If this option is specified, a temporary index is created which is automatically destroyed when the index is closed.
TO TEMP
The temporary index may be created in memory only .
Maurizio
Mr. Maurizio
Do you have complete sample ?
Thanks
Regards
Fafi
Hello
use clients
index on field->ADRESS TAG ADR TO TEMP TEMPORARY FOR field->COUNTRY == "USA"
Browse()
use
Hello Maurizio,
Thank you for sharing.
Is the index after you created automatically opened or do you have to open the
index file.
If you have in your example a clients.cdx do you have to close this before you create the temporary index file or do they coexistent
How to you change the index order.
First you have for example:
Use clients new
Clients-cdx with tag name, town, etc. is opened automatically.
How do you go ahead with your example?
Thanks in advance
Otto
Hello Otto
The index is automatically opened , and you don't have to close the previous index .
// How do you go ahead with your example?
If the natural index name is CLIENT.CDX :
set index to CLIENT
Regards MAurizio
xHarbour's OrdWildSeek( <cWildSeekExprn> )
Example:
OrdWildSeek( "/14/" )
I don't know whether the Soft seek solution work or not, Anyway it is just a hint
You need to have DBF indexed on the desired field.
Set Soft On
Seek "/14/"
Set Soft Off
Do While SubStr(Alias->FieldName,6,2) == "14"
....
Skip
Enddo
Mr.Rao's solution using xHarbours' OrdWildSeek( "/14/" ) seems to be a good one.
Regards
Anser
cRegex:="*/14/*"
cRegex:=HB_REGEXCOMP(cRegex)
dbgotop()
while !eof()
if ordkeyval() HAS cRegEx
// TA-DA!!! We got it!!!
?ordkeyno()
endif
dborderinfo(DBOI_SKIPREGEX,,,cRegex)
enddocPattern:="*/14/*"
nSec:=secondscpu()
dbgotop()
if !eof() .and. ! WildMatch(cPattern, ordkeyval())
dborderinfo(DBOI_SKIPWILD,,,cPattern)
endif
while !eof()
if WildMatch(cPattern, ordkeyval())
// TA-DA!!! We got it!!!
?ordkeyno()
endif
dborderinfo(DBOI_SKIPWILD,,,cPattern)
enddoMr.Rao's solution using xHarbours' OrdWildSeek( "*/14/*" ) seems to be a good one.
Mr. nageswaragunupudi.
For me "setfilter" is too slow (if you want to browse the data), especially with a very large databases. Much more effective to create the CUSTOM INDEX from the array of finded records.
PS. About your question, sorry, I use only xHarbour...
Hello Mr. Rao,
would you be so kind to advice me how to handle lower and upper case with OrdWildSeek.
I would need a search independent of the case.
Thanks in advance
Otto
Jeff,
Some years ago we helped a company to test several third party tools for such purpouse and finally implemented our own solution to make the fastest search on all fields of a DBF.
We found with great surprise that the solution was to open the DBF as a standard file with FOpen(), read a bunch of bytes in memory and perform a simple At() to locate a string. Once found, you substract the DBF header length, then divide the offset by the record size and you get the record number. At() is an extremelly fast function as it is directly performed by the processor.
These days that we use 32 bits flat memory, I guess there is no need to use a bunch of bytes, so the entire DBF may be loaded in memory doing a MemoRead() of the DBF file, or several bunchs if it is too large, so the code may get simpler.
We compared this way with other available third party tools, and we found that ours was the fastest one
Its worth to try it.