Full text Search

[Otto]

How could I manage a full text search in the whole database like LOCATE but in all fields?
Regards
Otto

[Antonio Linares]

Otto,

At( cText, MemoRead( "file.dbf" ) )

once found, substract the DBF header size, and divide it by the record size

[Otto]

Thank you. I there a limit for memoread: FW FWH

Regards
Otto

[Antonio Linares]

Otto,

MemoRead() is a Harbour function. There is no size limit (max. 4 gigs)

[Gale FORd]

If you have xHarbour from .com then you can use FTS (Full Text Search) to create index and search.

[hua]

At( cText, MemoRead( "file.dbf" ) )

once found, substract the DBF header size, and divide it by the record size

This is a neat trick! What further modification need to be done to take into account contents of memo fields also?

[Antonio Linares]

memo fields require a different approach as they are not stored in the DBF, but on an external file. You can search in such external file, and then you should search its offset into the DBF.

You may ask Przemek how to get the memo offset from the DBF

[StefanHaupt]

Otto,

How could I manage a full text search in the whole database like LOCATE but in all fields?
Regards
Otto

you can try the Hiper-Seek functions of xHarbour. That´s a very fast seek over all fields in dbf. But I don´t know, if it supports memo too.

Here is an example:

Code: Select all  Expand view

#INCLUDE "Fivewin.ch"
#include "dbinfo.ch"

//REQUEST RMDBFCDX
REQUEST DBFCDX
//REQUEST BMDBFCDX

PROCEDURE Main()
   FIELD FIRST, LAST, STREET, CITY
   LOCAL n, hs

   rddSetDefault( "DBFCDX" )
//   rddSetDefault( "BMDBFCDX" )
//   if ascan( rddList(1), "RMDBFCDX" ) != 0
//      rddSetDefault( "RMDBFCDX" )
//   endif
//   ? RddSetDefault ()
   use test
   hs := HS_INDEX( "test", "FIRST+LAST+STREET+CITY", 2, 0, , .T., 3 )

   /* Look for all records which have 'SHERMAN' string inside */
   HS_SET( hs, "SHERMAN" )
   while ( n := HS_NEXT( hs ) ) > 0
      dbgoto( n )
      if HS_VERIFY( hs ) > 0
         ? rtrim( FIRST+LAST+STREET+CITY )
      endif
   enddo
//   wait

   /* Does RDD support Record Map Filters? */
//   if dbinfo( DBI_RM_SUPPORTED )
      /* if yest then let set filter for all records with 'SHERMAN'
         word and look at them in browser */
      HS_FILTER( hs, "SHERMAN" )
      DbSetFilter( {|| "SHERMAN"},  "SHERMAN" )
      dbgotop()
      browse()
//   endif

   HS_CLOSE( hs )
   CLOSE ALL
   QUIT

RETURN


[Otto]

Hello Antonio,

I would like to use your solution.
But now I face the problem that some dbf files only return 4 or 5 bytes.
If I try to open the clients.dbf form the Fivewin sample this is the result:

local cText := MemoRead( "clientes.dbf" )

msginfo(ctext )





Otto,

At( cText, MemoRead( "file.dbf" ) )

once found, substract the DBF header size, and divide it by the record size
_________________
regards, saludos

Antonio Linares

[Antonio Linares]

Otto,

You can't see it as it has embedded zeroes. Try this:

MsgInfo( Len( ctext ) )

[Otto]

Thank you Antonio.

[Ollie]

Hi Stefan,

I get a "Unresolved External _HB_FUN_HS_INDEX" error when I try to compile your test. According to the help file I need - xhb.lib - is that correct? I can't find that lib on my PC, and yet I have xHarbour? Any ideas as to what I am doing wrong?

Did you ever find out if the Hyperseek works on MEMO fields too?

Antonio, do you know how to get the memo offset from the DBF if I use your method? (in case Hyperseek doesn't work for MEMOs)

[Antonio Linares]

Ollie,

> Antonio, do you know how to get the memo offset from the DBF

What RDD are you using ?

[Ollie]

DBFCDX

[Antonio Linares]

Ollie,

I guess that you could use:

DbInfo( DBI_BLOB_OFFSET )
http://www.ousob.com/ng/53guide/ng28fbc.php

and/or

DbFieldInfo( DBS_BLOB_OFFSET )
http://www.ousob.com/ng/53guide/ng25343.php