|
Mit den  FATS-Matchcode Befehlen läßt sich auf einfachste Weise ein Volltext-Index mit dem Inhalt der von Ihnen gewünschten Spalten bzw. Felder einer Datentabelle bzw. -datei erstellen. Dieser Index ermöglicht es FATS, jeden Datensatz durch Angabe beliebiger Begriffe in Sekundenbruchteilen zu finden. FATS stellt dem Anwendungsprogramm unmittelbar nach der Suche eine Liste aller gefundener Satznummern bzw. Primary-Keys zur Verfügung. Das nachfolgende C/C++ Beispiel demonstriert die Verwendung der FATS Matchcode-Befehle:
Jedes Wort und jede Zahl wird in den Index aufgenommen, es wird eine "invertierte Liste" erstellt.
/* FATS Extended Demo for MS-C FATS 02.30 (c) GCS Software, Udo Gertz 1993-1998 This program needs the extended version of FATS (FATSXM.OBJ) Use the logical order of an FATS index file to build the matchcode index. */ #include <stdio.h> #include <io.h> #include <fcntl.h> #include <sys\types.h> #include <sys\stat.h> #include <stdlib.h> #include <string.h> #include <memory.h> #include "FATS.h" 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; unsigned long dwHitId; char cChar; printf( "\nFATS Extended testprogram (Command 'MC', 'MB', 'MS' and 'MA')\n" ); printf( "\nThis Test Program was designed for Microsoft C\n\n" ); printf( "To compile and link the test program, use the following commands:\n\n" ); printf( " CL /Lp /A[?] /Ot MCSORT.C FATSX.OBJ FATS_MC[?].OBJ;\n" ); printf( " [?] memory model: S (small) , M (medium), C (compact), L (large)\n\n" ); printf( "\nPlease press the [ENTER] key ...\n\n" ); cChar = getchar(); /* 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. This example program uses the flag K#:# ("MC"-command) to create the matchcode index in sorted order. */ /* -------> Activation of Network Operation FATS is standardly equiped for the network environment. Nearly all commands can be executed both in single workstation and network environment. With the "Y" Auto Refresh command you determine the behavior of FATS accessing all index files. Normally it is sufficient to apply this instruction one time at the program start whereby the specified access mode will apply to all coming opened files, i.e. they are accessed either with network (Y\2) or single workstation access (Y\0). */ dwFATSRecno = FATSCALL( "Y\\2", &uFATSError, szFATSkey ); /* -------> Open data file */ printf( "Opening data file ...\n" ); hCustomer = open( "CUSTOMER.DAT", O_RDWR ); setmode( hCustomer, O_BINARY ); /* -------> Opening key file */ dwFATSRecno = FATSCALL( "O\\CUSTOMER.KEY\\2", &uFATSError, szFATSkey ); if ( uFATSError ) { printf( "\n" ); printf( "Error opening the file CUSTOMER.KEY\n" ); printf( "Please create the file using the test program TST1_ENG.C\n" ); return ( -1 ); } /* ======================================================================== 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. K#:# This switch activates the management of a primary key for this matchcode index file. The first value after the 'K' is the position of the data column within the key (1 == first part), the second value specifies the length of the data column valid as the key. Further adjustments are possible and described in detail in the user manual. */ printf( "\n" ); printf( "Creating matchcode index file ...\n" ); dwFATSRecno = FATSCALL( "MC\\CUSTSORT.FTS\\\\1\\K1:5\\I1\\I2\\I3", &uFATSError, szFATSkey ); /* "MC\{Filename}\\{FileNo}\K#:#\I1\I2\I3" The flag K#:# enables the management of a primary key within the matchcode file. FATS normaly only uses the record number during the generation of a result set. In specific situations, if e.g. the physical record number is not known, or does not correspond to the ID specified with the MB-command, the generation of a primary key becomes necessary. The browser commands then also make in addition to the record- or ID-number this key available via the FATSKEY-variable to the application. With the use of this flag, FATS generates a supplementary file with the file extension .FMK which is used for the sequential storage of the key. */ if ( uFATSError ) { printf( "\nFATS 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 in sorted order\n" ); printf( "\nPlease press the [ENTER] key ...\n\n" ); cChar = getchar(); dwCurRecno = 0L; strcpy( szCmnd, "F\\2\\2" ); /* */ for ( ;; ) { dwFATSRecno = FATSCALL( szCmnd, &uFATSError, szFATSkey ); if ( !uFATSError ) { lseek( hCustomer, (dwFATSRecno - 1) * sizeof(cust), SEEK_SET ); read( hCustomer, &cust, sizeof(cust) ); dwCurRecno++; sprintf( szCmnd, "MB\\1\\%lu\\", dwCurRecno ); /* Add the primary key to the command string */ strcat ( szCmnd, cust.ID ); 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 ); strcpy( szCmnd, "N\\2" ); } 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; } } /* ======================================================================== 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\\CUSTSORT.FTS\\1", &uFATSError, szFATSkey ); /* -------> Search in Search-Group 1 (NAME) */ 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 { dwHitId = FATSCALL( szCmnd, &uFATSError, szFATSkey ); if ( !uFATSError ) { /* */ sprintf( szCmnd, "S\\1\\2\\%s", szFATSkey ); dwFATSRecno = FATSCALL( szCmnd, &uFATSError, szFATSkey ); if ( !uFATSError ) { lseek( hCustomer, (dwFATSRecno - 1) * sizeof(cust), SEEK_SET ); read( hCustomer, &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", dwHitId ); } } while ( !uFATSError ); /* --------> Close all fats files */ dwFATSRecno = FATSCALL( "K", &uFATSError, szFATSkey ); close( hCustomer ); return ( 0 ); }
© 2008 GCS Software, Udo Gertz