 | FATS - Fast Access Tree System | |||
| Table of Contents | |||
| Programming Interfaces | |||
| Watcom C/C++ for DOS | |||
| | ||||||||||||||||||||
The This index enables FATS to find each data record by specification of any terms in fractions of a second. The following C/C++ example demonstrates the use of the FATS matchcode commands:
FATS matchcode commands create a full-text index with the content of your data tables or -files.
Every word and every number is incorporated into the index, an "inverted list" is generated.
 | "MC" Create Matchcode File (Define, create and open a Matchcode-Index-File.) |
| | "MB" Build Matchcode (Build the Matchcode-Index.) |
| | "O" Open Indexfile (Makes a index file available for access.) |
| | "MS" Search in Matchcode (Query the matchcode index, and setup an result set.) |
/*
FATS Extended Demo for Watcom-C
FATS 02.30
(c) GCS Software, Udo Gertz 1993-1998
This program needs the extended version of FATS (FATSXWE.EXE)
It tests the 'MC', 'MB', 'MS' and 'MA' commands
*/
#include <stdio.h>
#include <io.h>
#include <fcntl.h>
#include <sys\types.h>
#include <sys\stat.h>
#include <stdlib.h>
#include <string.h>
#include <mem.h>
#include "FATS.h"
/*
Calling FATS
All commands provided by FATS can be executed with one function:
unsigned long __cdecl FATSCALL(char *szCmnd,
unsigned short *uErrorcode, char *szFATSkey);
The meaning of the used parameters:
szCmnd With this command string you specify the actual
FATS command. The available commands are described
in the user manual.
nErrorcode Your application must always pass this variable as
the status parameter on a FATS call. After the
FATS call, the application should always check the
value of this variable. FATS returns a errorcode of
0 after a successful operation. FATS indicates any
errors which occur during processing by returning a
nonzero value in the errorcode variable.
In the manual you can find a list of all FATS
errorcodes and their possible causes.
szReturnKey This variable will contain the key value of a found
key after any normal search command (S,G,F,L,N,P,A,E).
in the case of a matchcode command:
If a primary key was generated during the creation of
the matchcode index file with the "K#:#" flag, it is
made available via this variable to the application
program.
Return Value: Record Number
*/
struct custdat {
char DELETEDMARK;
char ID[6];
char NAME[26];
char JOB[26];
char STREET[26];
char ZIP[6];
char CITY[21]; };
char szCmnd[512];
char szFATSkey[256];
unsigned short uFATSError;
unsigned long dwFATSRecno;
struct custdat cust;
int main ()
{
int hCustomer;
unsigned long dwCurRecno;
char cChar;
printf( "\nFATS Extended testprogram (Command 'MC', 'MB', 'MS' and 'MA')\n" );
printf( "\nThis Test Program was designed for Watcom C\n\n" );
printf( "To compile and link the test program, use the following command:\n\n" );
printf( " WCL /m[?] /l=dos /bt=dos TST2_ENG.C FATSXC[?]R.LIB \n" );
printf( " [?] memory model: s (small) , m (medium), c (compact), l (large)\n\n" );
printf( "\nPlease press the [ENTER] key ...\n\n" );
cChar = getchar();
/*
Load/Unload the FATS Extended Workstation Engine:
Load: FATSXWE
Unload: FATSXWE -unload
*/
/*
-------> Open data file
*/
printf( "Opening data file ...\n" );
hCustomer = open( "CUSTOMER.DAT", O_RDWR );
setmode( hCustomer, O_BINARY );
/*
========================================================================
Creating Matchcode Index
========================================================================
*/
/*
-------> Creating Matchcode Index File
With the command "MC" Create Matchcode File, the most important
query facilities are determined already while creating the
matchcode index file. With the search-group flag ("I#"), several
logically related data columns can be registered in a common index
so that a query to this index resp. search group extends automatically
over all these columns. A matchcode file manages up to 32 search
groups that can be used for joined queries (using the "AND"-operator).
In this example the following search groups are defined:
Search Group Fields
I1 NAME
I2 JOB
I3 ZIP & CITY
The syntax of the command string:
szCmnd = "MC\{FileName}\{Flags}\{FileNo}\{Col1def}[\{Col2def}]"
FileName Filename, perhaps with an additional path
(i.e. C:/DATA/CUSTOMER.FMS or CUSTOMER.FMS)
Flags Reserved, not used at the moment
FileNo File number
Col#def Definition of data column # (flags, separated by comma).
The content of the corresponding data columns is transferred
the commands "MB", "MI" and "MD" later in the order determined
by this command.
I# The content of the data column becomes part of search
group #. You can combine several columns into a logical
search group (e.g. first name, surname).
C The content of the data column is edited for word overall
searching, i.e. a search for "motorca" e.g. finds
"motorcar" and "motor caravan".
N Numbers are handled as words, i.e. during a search
according to "150", "12150" e.g. is also found.
Further adjustments are possible and described in detail
in the user manual.
*/ 
printf( "\n" );
printf( "Creating matchcode index file ...\n" );
dwFATSRecno = FATSCALL( "MC\\CUSTOMER.FTS\\\\1\\I1\\I2\\I3", &uFATSError, szFATSkey );
if ( uFATSError ) {
printf( "\n" );
if ( uFATSError == -1 ) {
printf( "FATS workstation engine is not activated.\n" );
printf( "Please start the program by entering FATSXWE at the command line.\n" );
} else {
printf( "FATS Errorcode: %i (Command: MC)\n", uFATSError );
}
return ( uFATSError );
}
/*
-------> Insert text into the matchcode index
After the matchcode file was generated, the content of the
data columns may be with the command "MB" Build Matchcode
inserted into the matchcode index. The position of the
data columns within the command string ("Col#data") corresponds
to that with the call of command Create Matchcode File ("MC")
determined definition.
The syntax of the command string:
szCmnd = "MB\{FileNo}\{RecNo}\{Col1data}[\{Col2data}[\{Col3data}]]"
FileNo File number
RecNo <> 0 Record- resp. id-number
== 0 Stop Build, no more records
Col#data Content of data column #
The following sample program code indexes contents of the
entire data file within a loop:
*/
printf( "\n" );
printf( "Building matchcode index\n" );
printf( "\nPlease press the [ENTER] key ...\n\n" );
cChar = getchar();
dwCurRecno = 0L;
/*
While indexing sequential data resources, the number specified
via "RecNo" should correspond to the physical record number
i.e. the first data record has number 1, the second record number 2..,
in the case of data records marked as deleted, the content of the
data columns is not specified ("MB\{FileNo}\{RecNo}").
The Build Matchcode (MB) command demands an ascending number as a
"RecNo" argument i.e. the matchcode can not usually be indexed in
the logical order of an index-key.
The example program MCSORT.c shows how an application
program might use the "MC" command to create the
matchcode index in sorted order.
*/
for ( ;; ) {
lseek( hCustomer, dwCurRecno * sizeof(cust), SEEK_SET );
if ( read(hCustomer, &cust, sizeof(cust)) == sizeof(cust) ) {
dwCurRecno++;
sprintf( szCmnd, "MB\\1\\%lu", dwCurRecno );
if ( !cust.DELETEDMARK ) {
sprintf( &szCmnd[ strlen(szCmnd) ], "\\%s\\%s\\%s %s",
cust.NAME,
cust.JOB,
cust.ZIP, cust.CITY );
}
dwFATSRecno = FATSCALL( szCmnd, &uFATSError, szFATSkey );
if ( uFATSError ) {
/*
If an error occurred during the execution of the "MB" command,
the matchcode index file is already closed by FATS.
*/
printf( "FATS Errorcode: %i (Command: MB)\n", uFATSError );
break;
}
printf( " %s --> RecNo %lu\n", cust.NAME, dwCurRecno );
} else {
/*
After the last record was inserted the creating process
has to be terminated with the command "MB\{FileNo}\0".
Because this command closes the matchcode index file you don't
have to do a close command.
*/
dwFATSRecno = FATSCALL( "MB\\1\\0", &uFATSError, szFATSkey );
break;
}
}
if ( !dwCurRecno ) {
printf( "\n" );
printf( "Error opening the file CUSTOMER.DAT\n" );
printf( "Please create the file using the test program TST1_ENG.C\n" );
return ( -1 );
}
/*
========================================================================
Matchcode Search
========================================================================
*/
/*
-------> Open matchcode index file
With the command "O" Open Indexfile you open an existing
matchcode index file with the opening flags defined with
the command "Y" Auto Refresh. After the file was opened
it can be accessed under the file number you specified.
*/
dwFATSRecno = FATSCALL( "O\\CUSTOMER.FTS\\1", &uFATSError, szFATSkey );
/*
-------> Search in Search-Group 1 (NAME)
The command "MS" Search in Matchcode searches the matchcode
index and fills the result set with the record- resp. ID-numbers
of data records which include the searched terms. If FATS finds
the requested terms, it returns the record- resp. ID-number of
the first hit in the "dwRecno" variable and a errorcode of 0.
The result set can then be read out with the browser commands
("MA", "ME", "MN", "MP" ...).
The syntax of the command string:
szCmnd = "MS\{FileNo}\{Flags}\{Total}\{SearchGrp1}[\{SearchGrp2}...]"
FileNo File number
Flags The search procedure can be adjusted by the specification
of different flags. You find a description of the flags
in the command reference.
Total Maximum number of hits in the result set:
0 All hits are set into the result set. This regulation
works very fast, however, no sorting occurs by means of
hit quality.
>0 It is attempted to put the specified number of hits into
the result set. These hits are subjected to a sorting
concerning their quality and then put into one of
7 sorting groups.
SearchGrp# The in search group # searched terms.
Different FATS commands can be used for further processing
of the result table, depending on the program logic.
The following example prints all hits on the output device:
*/
printf( "\n" );
printf( "We now search for all customers with the first name Michael.\n" );
printf( "\nPlease press the [ENTER] key ...\n\n" );
cChar = getchar();
strcpy( szCmnd, "MS\\1\\\\0\\michael" );
do {
dwFATSRecno = FATSCALL( szCmnd, &uFATSError, szFATSkey );
if ( !uFATSError ) {
lseek( hCustomer, (dwFATSRecno - 1) * sizeof(cust), SEEK_SET );
if ( read(hCustomer, &cust, sizeof(cust)) == sizeof(cust) ) {
printf( "%s | %s\n%s %s (#%lu)\n\n", cust.NAME, cust.JOB,
cust.ZIP, cust.CITY, dwFATSRecno );
}
sprintf( szCmnd, "MA\\1\\%lu", dwFATSRecno );
}
} while ( !uFATSError );
/*
The following browser commands are supported by FATS:
"MF" - Get First Result
"ML" - Get Last Result
"MP" - Get Previous Result
"MN" - Get Next Result
"MA" - Get Next Result After
"ME" - Get Previous Result Before
*/
/*
--------> Joined search in Search-Groups 2 (JOB) and 3 (ZIP/CITY)
*/
printf( "\n" );
printf( "We are now doing a joined search over the search groups\n" );
printf( "2 (Job) and 3 (Zip, City) to find all people from nevada\n" );
printf( "who are related to the transportation industry.\n" );
printf( "\nPlease press the [ENTER] key ...\n\n" );
cChar = getchar();
strcpy( szCmnd, "MS\\1\\\\0\\\\trans\\nev" );
do {
dwFATSRecno = FATSCALL( szCmnd, &uFATSError, szFATSkey );
if ( !uFATSError ) {
lseek( hCustomer, (dwFATSRecno - 1) * sizeof(cust), SEEK_SET );
if ( read(hCustomer, &cust, sizeof(cust)) == sizeof(cust) ) {
printf( "%s | %s\n%s %s (#%lu)\n\n", cust.NAME, cust.JOB,
cust.ZIP, cust.CITY, dwFATSRecno );
}
sprintf( szCmnd, "MA\\1\\%lu", dwFATSRecno );
}
} while ( !uFATSError );
/*
--------> Close matchcode index file
*/
dwFATSRecno = FATSCALL( "K\\1", &uFATSError, szFATSkey );
close( hCustomer );
return ( 0 );
}
© 2008 
GCS Software, Udo Gertz